JP2000040209A - Spin valve type thin-film element and thin film magnetic head using this spin valve type thin-film element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spin valve type thin-film element with which the exchange bond magnetic field can be made large by adequately adjusting the film thickness, etc., of a fixed magnetic layer and excellent thermal stability can be obtd. and a thin-film magnetic head formed by using this spin valve type thin-film element. SOLUTION: A PtMn alloy, which is high in blocking temp. and generates the exchange bond magnetic field with respect to a first fixed magnetic layer 12, is used for the antiferromagnetic layer 11. Further, the film thickness ratio of the first fixed magnetic layer 12 to the second fixed magnetic layer 14 and the film thicknesses, etc., of a nonmagnetic conductive layer and the antiferromagnetic layer are adequately adjusted, thereby, an exchange bond magnetic field of at least >=500 (Oe), more preferably 100 (Oe) can be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spin-valve type thin film element whose electric resistance changes depending on the relationship between the fixed magnetization direction of a fixed magnetic layer and the direction of magnetization of a free magnetic layer affected by an external magnetic field. A spin-valve thin film element capable of dividing a fixed magnetic layer into two layers and keeping the magnetization (ferri state) of the two fixed magnetic layers thermally stable; Related to the thin film magnetic head.

[0002]

2. Description of the Related Art FIG. 28 is a sectional view showing the structure of a conventional spin-valve thin film element when viewed from the side facing a recording medium. Reference numeral 1 denotes an underlayer formed of, for example, Ta (tantalum), and an antiferromagnetic layer 2
Are formed, and a fixed magnetic layer 3 is formed on the antiferromagnetic layer 2. The fixed magnetic layer 3 is formed in contact with the antiferromagnetic layer 2 so that the fixed magnetic layer 3
An exchange coupling magnetic field (exchange anisotropic magnetic field) is generated at the interface between the magnetic layer and the antiferromagnetic layer 2, and the magnetization of the fixed magnetic layer is fixed, for example, in the Y direction in the figure.

A nonmagnetic conductive layer 4 made of Cu or the like is formed on the fixed magnetic layer 3, and a free magnetic layer 5 is formed on the nonmagnetic conductive layer 4.
On both sides of the free magnetic layer 5, a hard bias layer 6 made of, for example, a Co-Pt (cobalt-platinum) alloy is provided.
6 are formed, and the hard bias layers 6 and 6 are magnetized in the X direction in the figure, so that the free magnetic layer 5 is formed.
Are aligned in the illustrated X direction. Thus, the variable magnetization of the free magnetic layer 5 and the fixed magnetization of the fixed magnetic layer 3 cross each other. Symbol 7 is T
Reference numeral 8 denotes a protective layer formed of, for example, Cu.

In this spin-valve type thin film element, a magnetic field leaking from a recording medium such as a hard disk causes
When the magnetization of the free magnetic layer 5 aligned in the direction fluctuates, the electric resistance changes in relation to the fixed magnetization of the fixed magnetic layer 3 fixed in the Y direction in the drawing, and the voltage change based on the change in the electric resistance value. Thereby, the leakage magnetic field from the recording medium is detected.

[0005]

Conventionally, as the antiferromagnetic layer 2, a NiMn alloy, a FeMn alloy,
Alternatively, an antiferromagnetic material such as NiO is used.
However, among these materials, in particular, FeMn alloys and NiO
The alloy has a blocking temperature of about 200 ° C. or lower and is a material lacking in thermal stability. In particular, in recent years, the environmental temperature in the apparatus becomes high, for example, 200 ° C. or more due to an increase in the number of rotations of the recording medium or the amount of sense current flowing from the conductive layer 8. Therefore, when an antiferromagnetic material having a low blocking temperature is used as the antiferromagnetic layer 2 of the spin-valve type thin film element, the exchange coupling magnetic field (exchange magnetic field) generated at the interface between the antiferromagnetic layer 2 and the pinned magnetic layer 3 is changed. As a result, the magnetization of the fixed magnetic layer 3 cannot be properly fixed in the Y direction in the drawing, resulting in a decrease in ΔMR (rate of change in resistance).

Since the blocking temperature is determined only by the antiferromagnetic material used for the antiferromagnetic layer 2, even if the structure of the spin-valve thin film element is improved, it is not possible to raise the blocking temperature itself. Can not. For example, JP-A-9-16920 describes an invention capable of improving the exchange coupling magnetic field by improving the structure of the fixed magnetic layer. However, in the present invention, since NiO is used as the antiferromagnetic layer, the blocking temperature is about 200 ° C., and even if the exchange coupling magnetic field at room temperature can be increased, the temperature in the device is 2 ° C.
When the temperature of the environment becomes close to or more than 00 degrees, the exchange coupling magnetic field of the spin-valve thin film element during the running of the recording medium becomes small or becomes zero, and it is impossible to obtain ΔMR at all.

On the other hand, NiMn alloys include NiO and F
Although the blocking temperature is higher than the eMn alloy, the properties such as corrosion resistance are poor. A magnetic material is required.

The present invention has been made to solve the above-mentioned conventional problems. In particular, the present invention improves the structure of the pinned magnetic layer and the material of the antiferromagnetic layer, and furthermore, appropriately adjusts the thickness of the pinned magnetic layer. It is an object of the present invention to provide a spin-valve thin-film element that can increase the exchange coupling magnetic field by adjusting the thickness and has excellent thermal stability, and a thin-film magnetic head using the spin-valve thin-film element.

[0009]

The present invention provides an antiferromagnetic layer and a fixed magnetic layer which is formed in contact with the antiferromagnetic layer and whose magnetization direction is fixed by an exchange coupling magnetic field with the antiferromagnetic layer. And a free magnetic layer formed on the fixed magnetic layer via a non-magnetic conductive layer and having a magnetization aligned in a direction crossing a magnetization direction of the fixed magnetic layer, wherein the fixed magnetic layer Is formed by being divided into two layers via a non-magnetic intermediate layer, wherein the fixed magnetic layer in contact with the antiferromagnetic layer is a first fixed magnetic layer, and the fixed magnetic layer in contact with the non-magnetic conductive layer is In the case of the second fixed magnetic layer, (thickness of the first fixed magnetic layer) / (thickness of the second fixed magnetic layer) is 0.33 to 0.95, or 1.05 to 1.05.
4 is within the range. In the present invention, the (thickness of the first fixed magnetic layer) / (the thickness of the second fixed magnetic layer) is 0.53 to 0.95, or 1.
More preferably, it is in the range of 0.05 to 1.8.

In the present invention, the thickness of the first fixed magnetic layer and the thickness of the second fixed magnetic layer are both within the range of 10 to 70 angstroms, and | the thickness of the first fixed magnetic layer. It is preferable that (thickness)-(thickness of second pinned magnetic layer) ≧≧ 2 angstroms. Further, in the present invention, the thickness of the first fixed magnetic layer and the thickness of the second fixed magnetic layer are:
Both are within the range of 10 to 50 angstroms, and | thickness of first fixed magnetic layer−thickness of second fixed magnetic layer |
More preferably, ≧ 2 angstroms. In the present invention, the free magnetic layer may be formed by being divided into two layers via a non-magnetic intermediate layer.

According to the present invention, the spin-valve thin film element includes an antiferromagnetic layer, a first fixed magnetic layer, a nonmagnetic conductive layer, a second fixed magnetic layer, a nonmagnetic conductive layer, and a free magnetic layer. A single spin-valve thin film element, wherein a free magnetic layer formed on the side in contact with the non-magnetic conductive layer is a first free magnetic layer, and Wherein the free magnetic layer is a second free magnetic layer, and the spin-valve thin-film element comprises:
A nonmagnetic conductive layer laminated above and below the free magnetic layer, and a second fixed magnetic layer / nonmagnetic layer laminated on one nonmagnetic conductive layer and below the other nonmagnetic conductive layer Dual spin valve type having three layers of an intermediate layer / first fixed magnetic layer and an antiferromagnetic layer laminated on one first fixed magnetic layer and below the other first fixed magnetic layer In the case where the free magnetic layer is a thin film element and one of the two free magnetic layers is a first free magnetic layer and the other free magnetic layer is a second free magnetic layer, (The thickness of the first free magnetic layer / the thickness of the second free magnetic layer)
It is preferably in the range of 0.56 to 0.83, or 1.25 to 5, and more preferably 0.61 to 0.
83, or 1.25 to 2.1.

The present invention also provides an antiferromagnetic layer and a fixed magnetic layer formed in contact with the antiferromagnetic layer and having a magnetization direction fixed by an exchange coupling magnetic field with the antiferromagnetic layer by heat treatment in a magnetic field. And a free magnetic layer formed on the fixed magnetic layer via a non-magnetic conductive layer and having a magnetization aligned in a direction crossing a magnetization direction of the fixed magnetic layer, wherein the fixed magnetic layer Is formed by being divided into two layers via a non-magnetic intermediate layer, wherein the fixed magnetic layer in contact with the antiferromagnetic layer is a first fixed magnetic layer, and the fixed magnetic layer in contact with the non-magnetic conductive layer is 2 as a fixed magnetic layer,
When the product of the saturation magnetization Ms and the film thickness t is a magnetic film thickness (magnetic moment), (magnetic film thickness of the first fixed magnetic layer) / (magnetic film thickness of the second fixed magnetic layer) ) Is 0.33
０．９0.95, or 1.05４4.

In the present invention, (the magnetic film thickness of the first fixed magnetic layer) / (the magnetic film thickness of the second fixed magnetic layer) is:
More preferably, it is in the range of 0.53 to 0.95, or 1.05 to 1.8. Further, in the present invention, the magnetic film thickness of the first fixed magnetic layer and the magnetic film thickness of the second fixed magnetic layer are both within the range of 10 to 70 (angstrom tesla), and | The magnetic film thickness of the fixed magnetic layer−the magnetic film thickness of the second fixed magnetic layer│ ≧ 2 (angstrom tesla). Further, in the present invention, the thickness of the first fixed magnetic layer and the thickness of the second fixed magnetic layer are both within the range of 10 to 50 (angstroms / tesla), and | the first fixed magnetic layer. The magnetic film thickness of the second fixed magnetic layer | ≧ 2 (angstrom tesla) is more preferable.

In the present invention, the free magnetic layer may be divided into two layers via a non-magnetic intermediate layer. In the present invention, the spin-valve thin film element includes an antiferromagnetic layer, a first fixed magnetic layer, a nonmagnetic conductive layer, a second fixed magnetic layer, a nonmagnetic conductive layer, and a free magnetic layer, which are formed one by one. A single spin-valve type thin film element, wherein a free magnetic layer formed on a side in contact with a nonmagnetic conductive layer is defined as a first free magnetic layer, and the other free magnetic layer is divided into two free magnetic layers. When the layer is a second free magnetic layer, and the spin-valve thin film element is a non-magnetic conductive layer laminated on and around the free magnetic layer, and one of the non-magnetic conductive layers A second pinned magnetic layer / non-magnetic intermediate layer /
A dual spin-valve thin-film element having three first fixed magnetic layers and an antiferromagnetic layer laminated on one first fixed magnetic layer and under the other first fixed magnetic layer. When one of the two free magnetic layers is a first free magnetic layer and the other free magnetic layer is a second free magnetic layer, the first free magnetic layer is divided into two layers. (Magnetic film thickness of magnetic layer / magnetic film thickness of second free magnetic layer) is preferably in the range of 0.56 to 0.83 or 1.25 to 5, more preferably 0 to 5. .6
It is in the range of 1 to 0.83, or 1.25 to 2.1.

Further, according to the present invention, the first pinned magnetic layer and the second pinned magnetic layer
The non-magnetic intermediate layer interposed between the pinned magnetic layer and Ru is Ru,
It is preferable to be formed of one or more alloys of Rh, Ir, Cr, Re, and Cu.

Further, according to the present invention, the spin-valve thin film element has an antiferromagnetic layer below the free magnetic layer, and a first fixed magnetic layer formed in contact with the antiferromagnetic layer. The thickness of the nonmagnetic intermediate layer interposed between the nonmagnetic conductive layer and the second pinned magnetic layer formed in contact with the nonmagnetic conductive layer is 3.6 to
It is preferably in the range of 9.6 angstroms, more preferably in the range of 4.0-9.4 angstroms. Alternatively, an antiferromagnetic layer is provided above the free magnetic layer, and a first fixed magnetic layer formed in contact with the antiferromagnetic layer and a second fixed magnetic layer formed in contact with the nonmagnetic conductive layer The thickness of the nonmagnetic intermediate layer interposed between the magnetic layer and the nonmagnetic intermediate layer is 2.5 to 6.4 angstroms, or 6.6.
It is preferably in the range of 〜10.7 Å, more preferably in the range of 2.8．6.2 Å or 6.8６10.3 Å. In the present invention, the antiferromagnetic layer is made of PtM
Preferably, it is formed of an n alloy.

In the present invention, the antiferromagnetic layer may have
Mn (where X is one or more of Pd, Ir, Rh, and Ru) or Pt-
Mn-X '(where X' is Pd, Ir, Rh, Ru,
Au, Ag, or one or more elements).

According to the present invention, the spin-valve thin film element comprises one of an antiferromagnetic layer, a first fixed magnetic layer, a nonmagnetic intermediate layer, a second fixed magnetic layer, a nonmagnetic conductive layer, and a free magnetic layer.
A single spin-valve thin film element formed layer by layer, wherein the thickness of the antiferromagnetic layer is preferably in the range of 90 to 200 Å, more preferably the thickness of the antiferromagnetic layer is , 100-200 angstroms.

Alternatively, the spin-valve thin-film element may include a nonmagnetic conductive layer laminated above and below a free magnetic layer, and a layer above one nonmagnetic layer and a layer below the other nonmagnetic layer. Three layers of a second pinned magnetic layer / a non-magnetic intermediate layer / a first pinned magnetic layer, and a layer stacked on one first pinned magnetic layer and under the other first pinned magnetic layer. A dual spin-valve thin-film element having an antiferromagnetic layer formed thereon, wherein the antiferromagnetic layer has a thickness of 100 to 200.
It is preferably in the range of Angstroms, more preferably in the range of 110 to 200 Angstroms. The non-magnetic intermediate layer interposed between the first free magnetic layer and the second free magnetic layer described above is Ru, R
Preferably, it is formed of one or more alloys of h, Ir, Cr, Re, and Cu. The thickness of the non-magnetic intermediate layer is preferably in the range of 5.5 to 10.0 angstroms, and more preferably 5.9.
９9.4 Å.

Further, the thin film magnetic head according to the present invention comprises:
A shield layer is formed above and below the above-mentioned spin-valve thin film element with a gap layer interposed therebetween. In the present invention, the fixed magnetic layer constituting the spin-valve thin film element is divided into two layers, and a non-magnetic intermediate layer is formed between the fixed magnetic layers divided into two layers. The magnetizations of the separated two pinned magnetic layers are magnetized in an antiparallel state, and the magnitude of the magnetic moment (magnetic film thickness) of one pinned magnetic layer and the magnetic moment of the other pinned magnetic layer Is a so-called ferry state. The exchange coupling magnetic field (RKKY interaction) generated between the two fixed magnetic layers is 1000 (Oe).
To 5000 (Oe), the two pinned magnetic layers are magnetized in an anti-parallel state in a very stable state.

The one fixed magnetic layer magnetized in the antiparallel (ferri state) is formed in contact with the antiferromagnetic layer.
The first fixed magnetic layer) is formed by an exchange coupling magnetic field (exchange anisotropic magnetic field) generated at the interface with the antiferromagnetic layer.
For example, the magnetization is fixed in a direction (height direction) away from the surface facing the recording medium. Thereby, the magnetization of the fixed magnetic layer (hereinafter, referred to as the second fixed magnetic layer) facing the first fixed magnetic layer via the nonmagnetic intermediate layer is opposite to the magnetization of the first fixed magnetic layer. It is fixed in a parallel state.

Conventionally, two layers of an antiferromagnetic layer and a pinned magnetic layer
In the present invention, the portion formed by the layers is replaced by the four layers of the antiferromagnetic layer / first fixed magnetic layer / nonmagnetic intermediate layer / second fixed magnetic layer.
Although the first pinned magnetic layer and the second pinned magnetic layer can be kept in a very stable magnetization state with respect to an external magnetic field by forming the first pinned magnetic layer and the second pinned magnetic layer, the first pinned magnetic layer Various conditions are required to improve the stability of magnetization of the second pinned magnetic layer.

First, the exchange coupling magnetic field (exchange anisotropic magnetic field) generated at the interface between the antiferromagnetic layer and the first pinned magnetic layer is to be increased. As described above, the magnetization of the first pinned magnetic layer is fixed in a certain direction by the exchange coupling magnetic field (exchange anisotropic magnetic field) generated at the interface with the antiferromagnetic layer, but the exchange coupling magnetic field is weak. Then, the fixed magnetization of the first fixed magnetic layer is not stable, and is likely to fluctuate due to an external magnetic field or the like. For this reason, it is preferable that the exchange coupling magnetic field (exchange anisotropic magnetic field) generated at the interface with the antiferromagnetic layer is large. PtM as a possible antiferromagnetic layer
An n alloy can be presented. In place of the PtMn alloy, an X—Mn (X is Pd, Ir, Rh, Ru) alloy or a Pt—Mn—X ′ (X ′ is Pd, Ir, Rh, Ru,
Au, Ag) alloys may be used.

These antiferromagnetic materials include NiO, FeMn alloy and Ni, which are conventionally used as antiferromagnetic materials.
It has excellent properties as an antiferromagnetic material, such as a large exchange coupling magnetic field, a high blocking temperature, and excellent corrosion resistance, as compared with a Mn alloy or the like.

FIG. 26 shows the present invention in which a PtMn alloy is used for the antiferromagnetic layer, and the fixed magnetic layer is divided into two layers, a first fixed magnetic layer and a second fixed magnetic layer, via a nonmagnetic intermediate layer. 7 is an RH curve of the spin-valve thin-film element of FIG. 7 and a conventional spin-valve thin-film element in which a fixed magnetic layer is formed as a single layer.

The film configuration of the spin-valve thin film element according to the present invention is as follows: from the bottom, Si substrate / alumina / Ta (30)
/ Antiferromagnetic layer; PtMn (200) / first fixed magnetic layer; Co (25) / nonmagnetic intermediate layer; Ru (7) / second fixed magnetic layer; Co (20) / Cu (20) / Co (1
0) / NiFe (40) / Ta (30), and the film configuration of the conventional spin-valve thin film element is S
i substrate / alumina / Ta (30) / antiferromagnetic layer; PtM
n (300) / pinned magnetic layer; Co (25) / Cu (2
0) / Co (10) / NiFe (40) / Ta (30)
It is. The numerical value in parentheses indicates the film thickness, and the unit is angstrom. Note that both the spin valve type thin film element of the present invention and the conventional spin valve type thin film element have a thickness of 200 (Oe) after film formation.
While applying a magnetic field of 260 ° C. for 4 hours.

As shown in FIG. 26, the ΔMR (resistance change rate) of the spin-valve type thin film element according to the present invention is between 7% and 8% at the maximum value. It can be seen that the decrease in ΔMR in the present invention is more gradual than that in the conventional spin-valve thin film element. Here, in the present invention, the magnitude of the external magnetic field when the value of ΔMR is half of the maximum value is defined as the exchange coupling magnetic field (Hex) generated by the spin-valve thin film element.

As shown in FIG. 26, in the conventional spin-valve thin film element, the maximum ΔMR is about 8%,
It can be seen that the external magnetic field (exchange coupling magnetic field (Hex)) when ΔMR is halved is about 900 (Oe) in absolute value. On the other hand, in the spin-valve type thin film element of the present invention, the maximum ΔMR is about 7.5%, which is slightly lower than the conventional one, but the external magnetic field (exchange coupling magnetic field ( Hex)) is about 2800 (Oe) in absolute value, which is much larger than the conventional value.

As described above, in the spin-valve thin film element of the present invention in which the fixed magnetic layer is divided into two layers, the spin-valve thin-film element in which the fixed magnetic layer is formed in one layer is more exchangeable. It can be seen that the coupling magnetic field (Hex) can be greatly increased, and the stability of the magnetization of the fixed magnetic layer can be improved as compared with the related art. Further, it can be seen that ΔMR does not decrease much in the present invention as compared with the related art, and a high ΔMR can be maintained.

FIG. 27 is a graph showing the relationship between the ambient temperature and the exchange coupling magnetic field using four types of spin-valve thin film elements. The first type of spin-valve thin-film element used is a spin-valve thin-film element of the present invention in which a PtMn alloy is used for the antiferromagnetic layer and the fixed magnetic layer is divided into two layers. , Si substrate /
Alumina / Ta (30) / antiferromagnetic layer; PtMn (20
0) / first fixed magnetic layer; Co (25) / non-magnetic intermediate layer; Ru (7) / second fixed magnetic layer; Co (20) / C
u (20) / Co (10) / NiFe (70) / Ta
(30).

The second type is a conventional example 1 in which a PtMn alloy is used for the antiferromagnetic layer and the fixed magnetic layer is formed as a single layer.
As the film configuration, from the bottom, a Si substrate / alumina / Ta
(30) / antiferromagnetic layer; PtMn (300) / pinned magnetic layer; Co (25) / Cu (25) / Co (10) / Ni
Fe (70) / Ta (30).

The third type is Conventional Example 2 in which NiO is used for the antiferromagnetic layer and the pinned magnetic layer is formed as a single layer. NiO (500) / fixed magnetic layer; Co (25) / C
u (25) / Co (10) / NiFe (70) / Ta
(30).

The fourth type is Conventional Example 3 in which an FeMn alloy is used for the antiferromagnetic layer and the fixed magnetic layer is formed as a single layer.
As the film configuration, from the bottom, a Si substrate / alumina / Ta
(30) / NiFe (70) / Co (10) / Cu (2
5) / pinned magnetic layer; Co (25) / antiferromagnetic layer; FeM
n (150) / Ta (30). Note that the above 4
Numerical values in parentheses for all types of film configurations indicate film thickness,
The unit is angstrom.

In the present invention and the conventional example 1 using PtMn for the antiferromagnetic layer, the film is subjected to a heat treatment at 260 ° C. for 4 hours while applying a magnetic field of 200 (Oe). In the conventional examples 2 and 3 using NiO and FeMn for the antiferromagnetic layer, no heat treatment was performed after the film formation.

As shown in FIG. 27, in the spin-valve thin film element of the present invention, when the ambient temperature is about 20 ° C., the exchange coupling magnetic field (Hex) is very high, about 2500 (Oe). On the other hand, N
In the conventional example 2 using iO and the conventional example 3 using FeMn for the antiferromagnetic layer, the exchange coupling magnetic field (Hex) is as low as about 500 (Oe) or less even at an ambient temperature of about 20 ° C. Further, in the conventional example 1 in which PtMn is used for the antiferromagnetic layer and the pinned magnetic layer is formed as a single layer, the ambient temperature is about 20 ° C.
, An exchange coupling magnetic field of about 1000 (Oe) is generated, and it can be seen that a larger exchange coupling magnetic field can be obtained than when NiO (Conventional Example 2) and FeMn (Conventional Example 3) are used for the antiferromagnetic layer. .

Japanese Patent Application Laid-Open No. 9-16920 discloses an RH curve of a spin-valve type thin film element in which NiO is used for an antiferromagnetic layer and a fixed magnetic layer is formed of two layers via a nonmagnetic intermediate layer. It is shown in FIG. According to FIG.
It is stated that the exchange coupling magnetic field (Hex) of (Oe) can be obtained, but this value is based on the exchange coupling magnetic field (approximately 10
00 (Oe): lower than that of the conventional example 1).

That is, when NiO is used for the antiferromagnetic layer, the pinned magnetic layer is divided into two layers, and the magnetization of the two fixed magnetic layers is changed to the ferrimagnetic state. Since the exchange coupling magnetic field is lower than when PtMn is used and the fixed magnetic layer is formed as a single layer, the use of a PtMn alloy for the antiferromagnetic layer provides a larger exchange coupling magnetic field. It is understood that this is preferable in that it can be performed.

As shown in FIG. 27, the antiferromagnetic layer has N
It can be seen that when an iO or FeMn alloy is used, the exchange coupling magnetic field becomes 0 (Oe) when the environmental temperature reaches about 200 ° C. This is because the NiO and FeM
This is because the blocking temperature of n is as low as about 200 ° C. On the other hand, in the conventional example 1 in which the PtMn alloy is used for the antiferromagnetic layer, the environmental temperature is about 400 ° C. and the exchange coupling magnetic field is 0 (Oe). It can be seen that the magnetization state of the layer can be kept very thermally stable.

Since the blocking temperature is governed by the material used as the antiferromagnetic layer, even in the spin-valve thin film element of the present invention shown in FIG. However, when a PtMn alloy is used for the antiferromagnetic layer as in the present invention, a higher blocking temperature can be obtained as compared with NiO or the like, and the pinned magnetic layer is divided into two layers. If the magnetization of the two pinned magnetic layers is set to the ferrimagnetic state, a very large exchange coupling magnetic field can be obtained until the blocking temperature is reached, and the magnetization state of the two pinned magnetic layers is changed to a thermal state. It is possible to maintain a stable state.

In the present invention, the non-magnetic intermediate layer formed between the first pinned magnetic layer and the second pinned magnetic layer may be one of Ru, Rh, Ir, Cr, Re, and Cu. Using two or more, the thickness of the non-magnetic intermediate layer,
The case where the antiferromagnetic layer is formed below the free magnetic layer and the case where it is formed above the free magnetic layer are different, and by forming the nonmagnetic intermediate layer with a film thickness in an appropriate range, The exchange coupling magnetic field (Hex) can be increased. The appropriate thickness of the non-magnetic intermediate layer will be described later in detail with reference to a graph.

Furthermore, according to the present invention, if the pinned magnetic layer is divided into two layers and formed, the exchange coupling magnetic field (H
ex) can be obtained, and the antiferromagnetic layer having the largest thickness in the film configuration of the spin-valve thin film element can be made thinner, so that the total thickness of the entire spin-valve thin film element can be reduced. Can be made thinner. Since the antiferromagnetic layer can be formed thin, even if the thickness of the gap layer formed above and below the spin-valve thin-film element is large enough to maintain sufficient insulation, the spin-valve thin-film element can be used. The distance from the gap layer formed on the lower side to the gap layer formed on the upper side of the spin-valve thin film element, that is, the gap length can be shortened, and the gap can be reduced.

By the way, as in the present invention, the fixed magnetic layer
When the first pinned magnetic layer and the second pinned magnetic layer are separated into two layers via the non-magnetic intermediate layer, the first pinned magnetic layer and the second pinned magnetic layer have the same thickness. Then, it was found through experiments that the exchange coupling magnetic field (Hex) and ΔMR (rate of change in resistance) were extremely reduced. When the first fixed magnetic layer and the second fixed magnetic layer are formed to have the same thickness, the magnetization states of the first fixed magnetic layer and the second fixed magnetic layer are antiparallel (ferri state). It is presumed that this is because the magnetization states of the first fixed magnetic layer and the second fixed magnetic layer are not in the antiparallel state. I can no longer do it.

Therefore, in the present invention, a large exchange coupling magnetic field can be obtained by forming the first fixed magnetic layer and the second fixed magnetic layer not with the same thickness but with different thicknesses. It is possible to increase ΔMR to the same level as before. The thickness ratio between the first fixed magnetic layer and the second fixed magnetic layer will be described later in detail with reference to a graph.

As described above, in the present invention, the pinned magnetic layer is divided into two layers of the first pinned magnetic layer and the second pinned magnetic layer via the non-magnetic intermediate layer. By using an antiferromagnetic material exhibiting a large exchange coupling magnetic field (exchange anisotropic magnetic field) at the interface with the first pinned magnetic layer, the exchange coupling magnetic field (Hex) of the entire spin-valve thin film element can be increased. Can be increased, and the magnetizations of the first fixed magnetic layer and the second fixed magnetic layer can be maintained in a thermally stable anti-parallel state (ferri state).

In the present invention, the film thickness ratio of the first pinned magnetic layer and the second pinned magnetic layer divided into two layers, the material of the non-magnetic intermediate layer and its thickness, or the film of the antiferromagnetic layer By optimizing the thickness and the like, the exchange coupling magnetic field of the entire spin-valve thin film element can be increased, and a high ΔMR can be obtained.

The spin-valve thin film element to which the present invention can be applied is a so-called single spin-valve thin film element in which an antiferromagnetic layer, a fixed magnetic layer, a nonmagnetic conductive layer, and a free magnetic layer are formed one by one. Alternatively, a so-called dual spin-valve thin film element in which a nonmagnetic conductive layer, a pinned magnetic layer, and an antiferromagnetic layer are formed above and below a free magnetic layer.

In the present invention, the free magnetic layer may be divided into two layers via a non-magnetic intermediate layer, similarly to the pinned magnetic layer. The magnetization of the first free magnetic layer and the second free magnetic layer formed via the non-magnetic intermediate layer is determined by the exchange coupling magnetic field (RKKY mutual magnetic field) generated between the first free magnetic layer and the second free magnetic layer. Action)
It is magnetized antiparallel and aligned in a direction crossing the magnetization of the fixed magnetic layers (the first fixed magnetic layer and the second fixed magnetic layer).

In the case of the fixed magnetic layers (the first fixed magnetic layer and the second fixed magnetic layer), the magnetization is fixed in a certain direction by the exchange coupling magnetic field (exchange anisotropic magnetic field) with the antiferromagnetic layer. Although the magnetization of the free magnetic layer fluctuates freely due to an external magnetic field, the fluctuation of the magnetization of the free magnetic layer depends on the relationship with the direction of the fixed magnetization of the fixed magnetic layer. The electric resistance changes, and a signal of an external magnetic field can be detected.

In the present invention, the ratio of the thickness of the first free magnetic layer to the thickness of the second free magnetic layer divided via the nonmagnetic intermediate layer, and the thickness of the nonmagnetic intermediate layer are By optimizing, the antiparallel state (ferri state) of the first pinned magnetic layer and the second pinned magnetic layer is kept thermally stable, and a high ΔMR comparable to that of the related art can be obtained. I have to. The thickness ratio of the first free magnetic layer and the second free magnetic layer and the thickness of the non-magnetic intermediate layer are as follows.
Details will be described later with reference to graphs.

[0050]

FIG. 1 is a cross-sectional view schematically showing a spin-valve thin film element according to a first embodiment of the present invention. FIG. 2 is a diagram showing the spin-valve thin film element shown in FIG. 3 is a cross-sectional view as viewed from the facing surface side of FIG. A shield layer is formed above and below the spin-valve thin-film element via a gap layer. A thin-film magnetic head (MR head) for reproduction is formed by the spin-valve thin-film element, the gap layer and the shield layer. It is configured. Note that an inductive head for recording may be laminated on the thin-film magnetic head for reproduction.

The thin-film magnetic head is provided at the trailing end of a floating slider provided in a hard disk device, and detects a recording magnetic field of a hard disk or the like. The moving direction of the magnetic recording medium such as a hard disk is the Z direction in the figure, and the direction of the leakage magnetic field from the magnetic recording medium is the Y direction.

The spin-valve thin-film element shown in FIGS. 1 and 2 is a so-called single-spin-valve thin-film element in which an antiferromagnetic layer, a pinned magnetic layer, a nonmagnetic conductive layer, and a free magnetic layer are formed one by one. , The lowest layer formed is
The underlayer 10 is made of a non-magnetic material such as Ta.
1 and 2, an antiferromagnetic layer 11 is formed on the underlayer 10, and a first fixed magnetic layer 12 is formed on the antiferromagnetic layer 11. As shown in FIG. 1, a non-magnetic intermediate layer 13 is formed on the first fixed magnetic layer 12, and a second fixed magnetic layer 14 is formed on the non-magnetic intermediate layer 13. . The first fixed magnetic layer 12
The second pinned magnetic layer 14 is made of, for example, a Co film, NiFe
It is formed of an alloy, a CoNiFe alloy, a CoFe alloy, or the like.

In the present invention, the antiferromagnetic layer 11
It is preferably formed of a PtMn alloy. PtM
The n alloy is an N alloy conventionally used as an antiferromagnetic layer.
Excellent corrosion resistance compared to iMn alloys and FeMn alloys, etc.
Moreover, the blocking temperature is high and the exchange coupling magnetic field (exchange anisotropic magnetic field) is large. In the present invention, instead of the PtMn alloy, X—Mn (where X is Pd, Ir, R
h, or Ru is one or more elements)
Alloy or Pt-Mn-X '(where X' is P
d, Ir, Rh, Ru, Au, or Ag).

The first fixed magnetic layer 12 shown in FIG.
And the arrow shown on the second pinned magnetic layer 14
The magnitude and direction of each magnetic moment
The magnitude of the magnetic moment is the saturation magnetization (Ms)
And the film thickness (t). The first shown in FIG.
The first fixed magnetic layer 12 and the second fixed magnetic layer 14 are made of the same material.
Material, for example, a Co film, and a second pinned magnetic layer
14 film thickness t_P2Is the thickness t of the first pinned magnetic layer 12_P1Yo
The second pinned magnetic layer 1
4 has a higher magnetic moment than the first pinned magnetic layer 12.
It is getting bigger. In the present invention, the first fixed magnetic
The layer 12 and the second pinned magnetic layer 14 have different magnetic moments.
Need to have a
Film thickness t of magnetic layer 12 _P1Is the thickness t of the second pinned magnetic layer 14
_P2It may be formed thicker.

As shown in FIG. 1, the first fixed magnetic layer 12 is magnetized in the illustrated Y direction, that is, in the direction away from the recording medium (height direction), and the second fixed magnetic layer 12 is opposed to the second fixed magnetic layer 12 via the nonmagnetic intermediate layer 13. The magnetization of the fixed magnetic layer 14 is magnetized antiparallel to the magnetization direction of the first fixed magnetic layer 12. The first pinned magnetic layer 12 is formed in contact with the antiferromagnetic layer 11,
By performing annealing (heat treatment) in a magnetic field, the first
An exchange coupling magnetic field (exchange anisotropic magnetic field) is generated at the interface between the pinned magnetic layer 12 and the antiferromagnetic layer 11. For example, as shown in FIG. It is fixed in the illustrated Y direction. The magnetization of the first pinned magnetic layer 12 is
When fixed in the Y direction in the figure, the magnetization of the second fixed magnetic layer 14 opposed via the nonmagnetic intermediate layer 12 is fixed in an antiparallel state to the magnetization of the first fixed magnetic layer 12.

In the present invention, the thickness ratio t _{P1 of} the first fixed magnetic layer 12 and the thickness ratio t _P2 of the second fixed magnetic layer 14 are optimized. Thickness t _P1 ) / (second
Thickness t _P2) of the fixed magnetic layer is preferably in the range of 0.33 to 0.95, or from 1.05 to 4. Within this range, the exchange coupling magnetic field can be increased. However, even within the above range, when the film thickness of the first fixed magnetic layer 12 and the second fixed magnetic layer 14 itself becomes large, the exchange coupling magnetic field tends to decrease. Therefore, in the present invention, the film thicknesses of the first fixed magnetic layer 12 and the second fixed magnetic layer 14 are optimized.

[0057] In the present invention, the thickness t _P2 of the first thickness of the pinned magnetic layer 12 t _P1 and the second fixed magnetic layer 14 is 10 to 70
1 angstrom and the first fixed magnetic layer 1
Preferably, the absolute value obtained by subtracting the thickness t _P2 of the second pinned magnetic layer 14 from the thickness t _P1 of No. 2 is 2 Å or more.

By properly adjusting the film thickness ratio and film thickness within the above range, it is possible to obtain an exchange coupling magnetic field (Hex) of at least 500 (Oe) or more. Here, the exchange coupling magnetic field is the magnitude of the external magnetic field when ΔMR is half of the maximum ΔMR (rate of change in resistance), and the exchange coupling magnetic field (Hex) is equal to the antiferromagnetic layer 11 and the first magnetic field. Exchange magnetic field (exchange anisotropic magnetic field) generated at the interface with the fixed magnetic layer 12 and the exchange coupling magnetic field (RKKY interaction) generated between the first fixed magnetic layer 12 and the second fixed magnetic layer 14. ) Is a comprehensive one including all magnetic fields.

In the present invention, the (thickness t _{P1 of} the first fixed magnetic layer) / (thickness t _{P2 of} the second fixed magnetic layer) is given by
More preferably, it is in the range of 0.53 to 0.95, or 1.05 to 1.8. The A in the above range, the film thickness t _P1 of the first pinned magnetic layer 12 has a thickness t _P2 of the second pinned magnetic layer 14 are both within the range of 10 to 50 angstroms, yet the first fixed Thickness t _{P1 of} magnetic layer 12
It is preferable that the absolute value obtained by subtracting the thickness t _P2 of the second pinned magnetic layer 14 from the above is 2 Å or more. Within the above range, the first fixed magnetic layer 12 and the second fixed magnetic layer 14
And the thickness t _{P1 of} the first pinned magnetic layer 12 and the thickness
By properly adjusting the thickness t _P2 of the fixed magnetic layer 14 described above, it is possible to obtain an exchange coupling magnetic field of at least 1000 (Oe) or more. If the film thickness ratio and the film thickness are within the above ranges, the exchange coupling magnetic field (Hex) can be increased, and at the same time,
ΔMR (resistance change rate) can be increased to the same level as in the related art.

As the exchange coupling magnetic field increases, the magnetization of the first fixed magnetic layer 12 and the magnetization of the second fixed magnetic layer 14 can be more stably maintained in an antiparallel state. By using a PtMn alloy having a high blocking temperature and generating a large exchange coupling magnetic field (exchange anisotropic magnetic field) at the interface with the first fixed magnetic layer 12 as the magnetic layer 11, the first fixed magnetic layer The magnetization states of the 12 and the second pinned magnetic layers 14 can be kept thermally stable.

The first pinned magnetic layer 12 and the second pinned magnetic layer 14 are formed of the same material, and the first pinned magnetic layer 12 and the second pinned magnetic layer 14 have the same thickness. It has been experimentally confirmed that when the values are the same, the exchange coupling magnetic field (Hex) and ΔMR extremely decrease. This is the Ms · t _P1 of the first pinned magnetic layer 12 (magnetic moment), when the Ms · t _P2 of the second pinned magnetic layer 14 (magnetic moment) are the same value, the first fixed The magnetization of the magnetic layer 12 and the magnetization of the second pinned magnetic layer 14 do not become antiparallel, and the amount of directional dispersion of the magnetization (the amount of magnetic moment in various directions) increases, which will be described later. This is because the relative angle to the magnetization of the free magnetic layer 16 cannot be properly controlled.

In order to solve such a problem, first, the Ms of the first fixed magnetic layer 12 and the second fixed magnetic layer
When t is set to a different value, that is, when the first fixed magnetic layer 12 and the second fixed magnetic layer 14 are formed of the same material, the first fixed magnetic layer 12 and the second fixed magnetic layer It is necessary to form the magnetic layers 14 with different thicknesses.

In the present invention, as described above, the thickness ratio between the first fixed magnetic layer 12 and the second fixed magnetic layer 14 is optimized. If the film thickness t _P1 of the fixed magnetic layer 12 and the thickness t _P2 of the second pinned magnetic layer 14 is approximately the same value, specifically, 0.95 to 1.0
The film thickness ratio in the range of 5 is excluded from the appropriate range.

Next, as in the present invention, a PtMn alloy or the like is formed on the antiferromagnetic layer 11 and then annealed in a magnetic field (heat treatment) after film formation.
In the case where an antiferromagnetic material that generates an exchange coupling magnetic field (exchange anisotropic magnetic field) at the interface with the first fixed magnetic layer 12 is used, the first fixed magnetic layer 12 and the second fixed magnetic layer Even if Ms · t of the fixed magnetic layer 14 is set to a different value, unless the direction and magnitude of the applied magnetic field during the heat treatment are properly controlled, the magnetization of the first fixed magnetic layer 12 and the second The amount of directional dispersion in the magnetization of the pinned magnetic layer 14 increases, or the magnetization cannot be properly controlled in the direction in which the magnetization is desired.

[0065]

[Table 1] In Table 1, Ms · t _{P1 of} the first pinned magnetic layer 12 is the second
By changing the magnitude and direction of the magnetic field during the heat treatment when it is larger than Ms · t _P2 of the fixed magnetic layer
It indicates in which direction the magnetizations of the first fixed magnetic layer 12 and the second fixed magnetic layer 14 are directed.

In (1) of Table 1, the direction of the magnetic field during the heat treatment is given to the left side in the figure by 100 to 1 k (Oe). In this case, Ms · t _P1 of the first pinned magnetic layer 12 is larger than the second fixed magnetic layer 12 by the second value.
Is larger than Ms · t _P2 of the fixed magnetic layer 14, the dominant magnetization of the first fixed magnetic layer 12 is directed leftward in the figure following the direction of the applied magnetic field. The magnetization is determined by the exchange coupling magnetic field (RKK) with the first pinned magnetic layer 12.
(Y-interaction) so as to be in an anti-parallel state.

In (2) of Table 1, 100 to 1 k
When the magnetic field of (Oe) is applied, the dominant magnetization of the first fixed magnetic layer 12 is directed rightward following the direction of the applied magnetic field, and the magnetization of the second fixed magnetic layer 14 is changed to the first fixed magnetic layer. It is antiparallel to the magnetization of layer 12.

In (3) of Table 1, 5k (Oe)
When the above magnetic field is applied, first, the dominant magnetization of the first fixed magnetic layer 12 is directed rightward following the direction of the applied magnetic field.
By the way, the first pinned magnetic layer 12 and the second pinned magnetic layer 1
Exchange coupling magnetic field (RKKY interaction) generated between
Is about 1 k (Oe) to 5 k (Oe), so
When a magnetic field of (Oe) or more is applied, the second pinned magnetic layer 14 also turns to the direction of the applied magnetic field, that is, to the right in the drawing.
Similarly, in (4) of Table 1, when a magnetic field of 5 k (Oe) or more is applied leftward, both the magnetizations of the first fixed magnetic layer 12 and the second fixed magnetic layer 14 are directed leftward in the drawing.

[0069]

[Table 2] In Table 2, Ms · t _{P1 of} the first pinned magnetic layer 12 is the second
When Ms · t _P2 of the fixed magnetic layer is also small, by changing the magnitude and direction of the applied magnetic field during the heat treatment,
It indicates in which direction the magnetizations of the first fixed magnetic layer 12 and the second fixed magnetic layer 14 are directed.

In (1) of Table 2, 100 to
When a magnetic field of 1 k (Oe) is applied, the magnetization of the second fixed magnetic layer 14 having a large Ms · t _P2 becomes dominant, and the magnetization of the second fixed magnetic layer 14 follows the direction of the applied magnetic field. Turn left in the figure. Due to the exchange coupling (RKKY interaction) between the first fixed magnetic layer 12 and the second fixed magnetic layer 14, the magnetization of the first fixed magnetic layer 12 is changed to the magnetization of the second fixed magnetic layer 14. Antiparallel to the other. Similarly, in (2) of Table 2, when a magnetic field of 100 to 1 k (Oe) is applied in the right direction in the drawing, the dominant magnetization of the second fixed magnetic layer 14 is oriented rightward in the drawing, and the first fixed The magnetization of the magnetic layer 12 is directed leftward in the figure.

In (2) of Table 2, 5k (O
e) When a magnetic field equal to or more than the above is applied, a magnetic field equal to or more than exchange coupling (RKKY interaction) between the first fixed magnetic layer 12 and the second fixed magnetic layer 14 is applied, whereby the first fixed magnetic layer The magnetizations of the layer 12 and the second pinned magnetic layer 14 are both
Turn right in the figure. In (4) of Table 2, 5
When a magnetic field of k (Oe) or more is applied, both the magnetizations of the first fixed magnetic layer 12 and the second fixed magnetic layer 14 are directed to the left in the drawing. Here, for example, when the magnetization of the first pinned magnetic layer 12 is to be directed rightward in the drawing, the appropriate magnetic field direction during heat treatment and the magnitude thereof are shown in Table 1 in (2).
(3) and (1) and (3) in Table 2.

In both Tables 1 (2) and 3 (3), the magnetization of the first fixed magnetic layer 12 having a large Ms · t _P1 is directed rightward under the influence of the rightward applied magnetic field during the heat treatment. At this time, the magnetization of the first fixed magnetic layer 12 is fixed to the right by an exchange coupling magnetic field (exchange anisotropic magnetic field) at the interface with the antiferromagnetic layer 11 generated by the heat treatment. In Table 1 (3), when the magnetic field of 5k (Oe) or more is removed,
The magnetization of the second pinned magnetic layer 14 is reversed by the exchange coupling magnetic field (RKKY interaction) generated between the second pinned magnetic layer 14 and the first pinned magnetic layer 12 and turns to the left. .

Similarly, in Tables 2 (1) and 3 (3), the magnetization of the first pinned magnetic layer 12 turned to the right
It is fixed to the right by an exchange coupling magnetic field (exchange anisotropic magnetic field) at the interface with 1. In Table 2 (3), 5k (O
e) When the above magnetic field is removed, the second pinned magnetic layer 14 is removed.
The magnetization of the second fixed magnetic layer 14 is reversed by an exchange coupling magnetic field (RKKY interaction) generated between the first fixed magnetic layer 12 and the first fixed magnetic layer 12, and is fixed to the left.

As shown in Tables 1 and 2, the magnitude of the magnetic field applied during the heat treatment is 100 to 1 k (O
e) or 5k (Oe) or more and 1k (Oe)
The magnitude of the magnetic field in the range of ５5 k (Oe) is out of the proper range. This is for the following reasons. By applying a magnetic field, the magnetization of the fixed magnetic layer having a large Ms · t tends to move in the direction of the magnetic field. However, if the magnitude of the magnetic field during the heat treatment is between 1 k (Oe) and 5 k (Oe), even the magnetization of the fixed magnetic layer having a small Ms · t is strongly affected by the magnetic field, and I will go over. Therefore, the exchange coupling magnetic field (RKK) generated between the fixed magnetic layers
The magnetizations of the two fixed magnetic layers that are about to become antiparallel due to the Y interaction do not become antiparallel under the influence of the strong magnetic field, and the magnetizations of the fixed magnetic layers tend to go in various directions. In other words, the so-called magnetization dispersion increases, and the magnetization of the two fixed magnetic layers cannot be appropriately magnetized in an antiparallel state. Therefore, in the present invention, 1 k (Oe) to 5 k (Oe)
The magnitude of the magnetic field is out of the proper range. The reason why the magnitude of the magnetic field during the heat treatment is set to 100 (Oe) or more is that the magnetization of the fixed magnetic layer having a large Ms · t cannot be directed in the direction of the applied magnetic field unless a magnetic field of this magnitude is applied. It is.

The method of controlling the magnitude and the direction of the magnetic field during the heat treatment described above is applicable to any antiferromagnetic material as long as the antiferromagnetic layer 11 requiring heat treatment is used. This is applicable even when, for example, a NiMn alloy conventionally used as the antiferromagnetic layer 11 is used.

As described above, according to the present invention, the exchange coupling magnetic field (Hex) can be increased by keeping the thickness ratio of the first fixed magnetic layer 12 and the second fixed magnetic layer 14 within an appropriate range. , The first fixed magnetic layer 12 and the second fixed magnetic layer 1
The magnetization of No. 4 can be maintained in an anti-parallel state (ferri state) that is thermally stable, and ΔMR (resistance change rate) can be ensured at about the same level as in the related art.

Further, by appropriately controlling the magnitude and direction of the magnetic field during the heat treatment, the first pinned magnetic layer 1
It is possible to control the magnetization directions of the second and second pinned magnetic layers 14 to the desired directions.

As described above, the magnetic moment (magnetic film thickness) can be determined by the product of the saturation magnetization Ms and the film thickness t. For example, in the case of bulk solid NiFe, the saturation magnetization Ms is about 1.0T (Tesla) and the bulk solid Co, the saturation magnetization Ms is about 1.
It is known to be 7T. Therefore, the NiFe
When the thickness of the film is 30 Å, the Ni
The magnetic film thickness of the Fe film is 30 Å / tesla. The magnetostatic energy of the ferromagnetic film when a magnetic field is applied from the outside is proportional to the product of the magnetic film thickness and the external magnetic field. When the magnetic film is in the ferri state due to the RKKY interaction via the non-magnetic intermediate layer, the ferromagnetic film having a larger magnetic film thickness tends to be directed to the direction of the external magnetic field.

However, in the case of a ferromagnetic film in lamination contact with a nonmagnetic film such as tantalum (Ta), ruthenium (Ru), or copper (Cu), or in a ferromagnetic film in lamination contact with an antiferromagnetic layer such as a PtMn film. In the case of, since the nonmagnetic film atoms or antiferromagnetic film atoms and the ferromagnetic film atoms (Ni, Fe, Co) directly contact each other, the saturation magnetization Ms of the ferromagnetic film near the interface with the nonmagnetic film or antiferromagnetic film Is known to be smaller than the saturation magnetization Ms of the bulk solid. Further, when a heat treatment is applied to the laminated multilayer film including the ferromagnetic film, the non-magnetic film, and the antiferromagnetic layer, the heat treatment promotes interfacial diffusion, and a distribution in the thickness direction of the saturation magnetization Ms of the ferromagnetic film occurs. It is known.
That is, the saturation magnetization Ms near the nonmagnetic film or the antiferromagnetic layer is small, and the saturation magnetization Ms approaches the saturation magnetization Ms of the bulk solid as the distance from the interface with the nonmagnetic film or the antiferromagnetic film increases. .

The decrease in the saturation magnetization Ms of the non-magnetic film or the ferromagnetic film near the anti-ferromagnetic layer depends on the material of the non-magnetic film, the material of the anti-ferromagnetic layer, the material and the stacking order of the ferromagnetic film, and the heat treatment temperature. To be precise, it must be determined under each specified condition. The magnetic film thickness in the present invention is a value calculated in consideration of the amount of decrease in the saturation magnetization Ms caused by thermal diffusion between the nonmagnetic film and the antiferromagnetic layer.

In order to obtain an exchange coupling magnetic field at the interface between the PtMn film and the ferromagnetic film, it is necessary to form a diffusion layer at the interface between the PtMn film and the ferromagnetic film by heat treatment. The decrease in the saturation magnetization Ms of the ferromagnetic film due to
This depends on the stacking order of the tMn film and the ferromagnetic film.

In particular, as shown in FIG. 1, when the antiferromagnetic layer 11 is formed below the free magnetic layer 16, the antiferromagnetic layer 11 and the first pinned magnetic layer 12 A thermal diffusion layer is easily generated at the interface with the first fixed magnetic layer 12, so that the magnetic thickness of the first fixed magnetic layer 12 is smaller than the actual thickness t _P1 . However, the first fixed magnetic layer 1
If the magnetic film thickness of the second fixed magnetic layer 14 is too small, the difference in magnetic film thickness (magnetic moment) from the second pinned magnetic layer 14 becomes too large, and There is a problem that an increase in the ratio leads to a decrease in the exchange coupling magnetic field.

That is, as in the present invention, the antiferromagnetic layer 11 which requires heat treatment to generate an exchange coupling magnetic field at the interface with the first fixed magnetic layer 12 is used. In order to set the magnetization states of the second pinned magnetic layer 12 and the second pinned magnetic layer 14 to the ferri state, the first pinned magnetic layer 12 and the second pinned magnetic layer
Not only is the thickness of the fixed magnetic layer 14 optimized, but also the first
Unless the magnetic film thickness of the fixed magnetic layer 12 and the second fixed magnetic layer 14 is optimized, a stable magnetization state cannot be maintained.

As described above, if there is no difference in the magnetic film thickness between the first fixed magnetic layer 12 and the second fixed magnetic layer 14 to some extent, the magnetization state is unlikely to be in the ferrimagnetic state. If the difference between the magnetic thicknesses of the magnetic layer 12 and the second pinned magnetic layer 14 is too large, the exchange coupling magnetic field is undesirably reduced. Therefore, in the present invention, the same as the film thickness ratio of the first fixed magnetic layer 12 and the second fixed magnetic layer 14,
(Magnetic film thickness of first fixed magnetic layer 12) / (magnetic film thickness of second fixed magnetic layer 14) is in the range of 0.33 to 0.95, or 1.05 to 4. Preferably, there is.
Further, in the present invention, the first fixed magnetic layer 12 and the second fixed magnetic layer 14 have a magnetic thickness within a range of 10 to 70 (angstrom tesla) and a first fixed magnetic layer The absolute value obtained by subtracting the magnetic film thickness of the second pinned magnetic layer 14 from the magnetic film thickness of the layer 12 is preferably 2 (angstrom tesla) or more.

The ratio of (the magnetic film thickness of the first fixed magnetic layer 12) / (the magnetic film thickness of the second fixed magnetic layer 14) is set to 0.
More preferably, it is in the range of 53 to 0.95, or 1.05 to 1.8. Also, within the above range, the magnetic film thickness of the first pinned magnetic layer 12 and the second pinned magnetic layer 1
4 has a magnetic film thickness of 10 to 50 (angstrom.
Tesla) and the first fixed magnetic layer 12
The absolute value obtained by subtracting the magnetic film thickness of the second pinned magnetic layer 14 from the magnetic film thickness of the second fixed magnetic layer 14 is preferably 2 (angstrom tesla) or more.

Next, the nonmagnetic intermediate layer 1 interposed between the first pinned magnetic layer 12 and the second pinned magnetic layer 14 shown in FIG.
3 will be described. In the present invention, the first pinned magnetic layer 1
The non-magnetic intermediate layer 13 interposed between the second pinned magnetic layer 14 and the second pinned magnetic layer 14 may be formed of one or more alloys of Ru, Rh, Ir, Cr, Re, and Cu. preferable.

In the present invention, depending on whether the antiferromagnetic layer 11 is formed below or above the free magnetic layer 16 to be described later, the appropriate thickness of the nonmagnetic intermediate layer 13 is determined. Is changing. When the antiferromagnetic layer 11 is formed below the free magnetic layer 16 as shown in FIG. 1, the thickness of the nonmagnetic intermediate layer 13 is 3.6 to 9.6
Preferably, it is formed in the range of Å. Within this range, an exchange coupling magnetic field (Hex) of 500 (Oe) or more can be obtained. It is more preferable that the thickness of the nonmagnetic intermediate layer 13 be in the range of 4 to 9.4 angstroms, since an exchange coupling magnetic field of 1000 (Oe) or more can be obtained.

It has been experimentally confirmed that the exchange coupling magnetic field is extremely reduced when the thickness of the non-magnetic intermediate layer 13 is formed in a dimension other than the dimensions described above. That is, when the nonmagnetic intermediate layer 13 is formed with dimensions other than the above dimensions, the first fixed magnetic layer 12 and the second fixed magnetic layer
Are hardly in an anti-parallel state (ferri state), and the magnetization state becomes unstable.

As shown in FIG. 1, the second pinned magnetic layer 14
A nonmagnetic conductive layer 15 made of Cu or the like is formed thereon, and a free magnetic layer 16 is formed on the nonmagnetic conductive layer 15. As shown in FIG. 1, the free magnetic layer 16 is formed by two layers,
The layer denoted by reference numeral 17 formed on the side in contact with 5 is formed of a Co film. The other layer 18 is formed of a NiFe alloy, a CoFe alloy, a CoNiFe alloy, or the like. Note that Co on the side in contact with the nonmagnetic conductive layer 15
The reason for forming the film layer 17 is that diffusion of a metal element or the like at the interface with the nonmagnetic conductive layer 15 made of Cu can be prevented, and ΔMR (resistance change rate) can be increased. Reference numeral 19 denotes a protective layer formed of Ta or the like. Further, as shown in FIG.
On both sides of the laminate up to, for example, a Co-Pt alloy or Co
-Hard bias layer 1 made of Cr-Pt alloy or the like
30 and a conductive layer 131 formed of Cu or Cr. The magnetization of the free magnetic layer 16 is magnetized in the X direction in the drawing under the influence of the bias magnetic field of the hard bias layer. ing.

In the spin-valve type thin film element shown in FIG. 1, the free magnetic layer 16, the nonmagnetic conductive layer 1
5 and the second pinned magnetic layer 14 are supplied with a sense current. When a magnetic field is applied from the recording medium in the Y direction shown in FIG. 1, the magnetization of the free magnetic layer 16 changes from the X direction shown in the figure to the Y direction. At the interface between the nonmagnetic conductive layer 15 and the second pinned magnetic layer 14, scattering of conduction electrons depending on the spin occurs, so that the electric resistance changes and a leakage magnetic field from the recording medium is detected.

Incidentally, the sense current actually flows also at the interface between the first pinned magnetic layer 12 and the non-magnetic intermediate layer 13. The first pinned magnetic layer 12 is not directly involved in ΔMR, and the first pinned magnetic layer 12 is for fixing the second pinned magnetic layer 14 involved in ΔMR in an appropriate direction.
In other words, it is a layer that plays an auxiliary role. For this reason, the flow of the sense current through the first pinned magnetic layer 12 and the non-magnetic intermediate layer 13 causes shunt loss (current loss), but the amount of the shunt loss is very small. It is possible to obtain a ΔMR that is almost the same as the above.

In the present invention, the antiferromagnetic layer 1 is divided by dividing the pinned magnetic layer into the first pinned magnetic layer 12 and the second pinned magnetic layer 14 via the non-magnetic intermediate layer 13.
1 has a large exchange coupling magnetic field (He
x) More specifically, it was found through experiments that an exchange coupling magnetic field of 500 (Oe) or more could be obtained.

Conventionally, when a PtMn alloy is used as the antiferromagnetic layer 11 of a single spin valve thin film element,
Unless a film thickness of at least 200 Å or more is secured, an exchange coupling magnetic field of 500 (Oe) or more cannot be obtained.
At least 90 angstroms or more,
It is possible to obtain an exchange coupling magnetic field of 500 (Oe) or more. If the thickness is set to 100 Å or more, an exchange coupling magnetic field of 1000 (Oe) or more can be obtained. The numerical range of the film thickness of the antiferromagnetic layer 11 is for a single spin-valve thin film element.
In the case of a so-called dual spin valve type thin film element in which the antiferromagnetic layer is formed above and below the free magnetic layer, the appropriate thickness range is slightly different. The case of the dual spin-valve thin film element will be described later. As described above, according to the present invention, the antiferromagnetic layer 11 having the largest film thickness among the spin-valve thin film elements can be formed with a film thickness that is less than half the thickness of the conventional one. It is possible to reduce the film thickness of the entire device.

FIG. 13 is a cross-sectional view of the structure of the read head on which the spin-valve thin film element is formed, as viewed from the side facing the recording medium. Reference numeral 120 denotes a lower shield layer formed of, for example, a NiFe alloy, and a lower gap layer 121 is formed on the lower shield layer 120. On the lower gap layer 121, a spin-valve thin film element 122 according to the present invention is formed. On both sides of the spin-valve thin film element 122, a hard bias layer 123 and a conductive layer 124 are formed. Further, an upper gap layer 125 is formed on the conductive layer 124, and an upper shield layer 12 made of a NiFe alloy or the like is formed on the upper gap layer 125.
6 are formed.

The lower gap layer 123 and the upper gap layer 125 are made of, for example, SiO ₂ or Al ₂ O ₃ (alumina).
And the like. As shown in FIG. 13, the lower gap layer 121
The length up to 5 is the gap length Gl, and the smaller the gap length Gl, the higher the recording density.

In the present invention, as described above, the antiferromagnetic layer 1
1 can be reduced, the overall thickness of the spin-valve thin-film element 122 can be reduced.
It is possible to shorten l. Also the lower gap layer 1
Even if the film thicknesses of the upper gap layer 21 and the upper gap layer 125 are relatively large, the gap length Gl can be reduced as compared with the related art, and the lower gap layer 121 and the upper gap layer 12 can be formed.
By forming the layer 5 thick, sufficient insulation can be ensured.

The spin-valve thin-film element shown in FIG. The magnetic conductive layer 15, the free magnetic layer 16, and the protective layer 19 are formed, and in a process after the film formation, annealing (heat treatment) in a magnetic field is performed.

In the spin-valve thin film device shown in FIG.
The thickness t _P1 of the first pinned magnetic layer 12 is formed smaller than the thickness t _P2 of the second pinned magnetic layer 14, and the magnetic moment (Ms · t _P1 ) of the first pinned magnetic layer 12 is formed. Is set smaller than the magnetic moment (Ms · t _P2 ) of the second pinned magnetic layer 14. In this case, the direction of the magnetization of the first pinned magnetic layer 14 is set to 10
A magnetic field of 0 to 1000 (Oe) is applied, or a magnetic field of 5 k (Oe) or more is applied in a direction in which magnetization is desired.

As shown in FIG. 1, the first pinned magnetic layer 12
When it is desired to fix the magnetization in the illustrated Y direction, by referring to Table 2 described above, 10
A magnetic field of 0 to 1 k (Oe) (see Table 2 (1)) is applied, or 5 k (Oe) in the Y direction (see Table 2 (3)).
It can be seen that the above magnetic field may be applied.

100 to 1 k (Oe) in the direction opposite to the Y direction
The magnetic moment (Ms · t _P2 )
The magnetization of the second pinned magnetic layer 14 having a large value is magnetized in a direction opposite to the Y direction, and the first pinned magnetic layer 14 is likely to be antiparallel magnetized by an exchange coupling magnetic field (RKKY interaction) with the second pinned magnetic layer. The magnetization of the fixed magnetic layer 12 is oriented in the Y direction in the drawing,
An exchange coupling magnetic field (exchange anisotropic magnetic field) generated at the interface with the antiferromagnetic layer 11 causes the first pinned magnetic layer 1
2 is fixed in the illustrated Y direction. By fixing the magnetization of the first fixed magnetic layer 12 in the Y direction in the drawing, the second
Is fixed in antiparallel to the magnetization of the first fixed magnetic layer 12.

Alternatively, when a magnetic field of 5 k (Oe) or more is applied in the illustrated Y direction, the magnetizations of the first fixed magnetic layer 12 and the second fixed magnetic layer 14 are both magnetized in the illustrated Y direction, and the first fixed magnetic layer The magnetization of the layer 12 is changed by an exchange coupling magnetic field (exchange anisotropic magnetic field) generated at the interface with the antiferromagnetic layer 11, as shown in FIG.
Fixed in the direction. When the applied magnetic field of 5 k (Oe) or more is removed, the magnetization of the second pinned magnetic layer 14 is reversed by the exchange coupling magnetic field (RKKY interaction) with the first pinned magnetic layer 12, and the direction opposite to the Y direction shown in the drawing. Fixed to Alternatively, when the magnetic moment of the first pinned magnetic layer 12 is larger than the magnetic moment of the second pinned magnetic layer 14, the magnetic moment of the first pinned magnetic layer 12 is set to 100 to 1000 (Oe) or a magnetic field of 5 k (Oe) or more is applied.

The spin-valve thin film element shown in FIG. 1 is the most important part of the reproducing head (thin film magnetic head). First, a gap layer is formed on a lower shield layer made of a magnetic material. Thereafter, the spin-valve thin film element is formed. Thereafter, when an upper shield layer is formed on the spin-valve thin film element via a gap layer,
A reproducing head (MR head) is completed. Note that a recording inductive head having a core and a coil made of a magnetic material may be laminated on the reproducing head. In this case, it is preferable that the upper shield layer is also used as a lower core layer of the inductive head. Note that, in the spin-valve thin-film element shown in FIG. 3 and thereafter, shield layers are formed above and below the spin-valve thin-film element shown in FIG.

FIG. 3 is a cross-sectional view schematically showing the structure of a spin-valve thin film element according to a second embodiment of the present invention.
FIG. 4 is a cross-sectional view of the spin-valve thin film element shown in FIG. 3 as viewed from a surface facing a recording medium. This spin valve thin film element is a single spin valve thin film element formed by reversing the film configuration of the spin valve thin film element of FIG. That is, in the spin-valve thin film element shown in FIG. 3, the underlayer 10, the NiFe film 22, the Co film 23
(The free magnetic layer 21 including the NiFe film 22 and the Co film 23), the nonmagnetic conductive layer 24, the second pinned magnetic layer 25, the nonmagnetic intermediate layer 26, the first pinned magnetic layer 27, and the antiferromagnetic layer 2
8 and the protective layer 29 are stacked in this order.

The antiferromagnetic layer 28 is preferably formed of a PtMn alloy, or is replaced with X—Mn (where X is Pd, Ir, R
h, or Ru is one or more elements)
Alloy or Pt-Mn-X '(where X' is P
d, Ir, Rh, Ru, Au, or Ag).

Also in this spin-valve thin film element,
The thickness t of the first pinned magnetic layer 27 _P1And the second fixed magnet
Ratio t of the conductive layer 25_P2Is (film thickness t of first pinned magnetic layer)
_P1) / (Film thickness t of second pinned magnetic layer)_P2) Is from 0.33
0.95 or 1.05-4
Preferably, more preferably, 0.53 to 0.95
Or in the range of 1.05 to 1.8. Moreover, the first
Thickness t of pinned magnetic layer 27_P1And the second pinned magnetic layer 25
Film thickness t_P2Is within the range of 10 to 70 angstroms, and
Thickness t of the first pinned magnetic layer 27_P1From the second fixed magnetism
Thickness t of layer 25 _P2Absolute value minus 2 Angstroms
It is preferable that it is above. More preferably, the first
Thickness t of pinned magnetic layer 27_P1And the second pinned magnetic layer 25
Film thickness t_P2Is within the range of 10 to 50 angstroms, and
Thickness t of the first pinned magnetic layer 27 _P1From the second fixed magnetism
Thickness t of layer 25_P2Absolute value minus 2 Angstroms
That is all.

As described above, if there is no difference in the magnetic film thickness between the first fixed magnetic layer 27 and the second fixed magnetic layer 25 to some extent, the magnetization state is unlikely to be in the ferrimagnetic state. An excessively large difference in magnetic film thickness between the magnetic layer 27 and the second pinned magnetic layer 25 is not preferable because the exchange coupling magnetic field is reduced. Therefore, in the present invention, the same as the film thickness ratio of the first fixed magnetic layer 27 and the second fixed magnetic layer 25,
(Magnetic film thickness Ms · t _{P1 of} first fixed magnetic layer 27) /
(The magnetic film thickness Ms · t _{P2 of} the second pinned magnetic layer 25)
It is preferably in the range of 0.33 to 0.95, or 1.05 to 4. In the present invention also the magnetic film thickness Ms · t _P2 of the magnetic film thickness Ms · t _P1 and the second fixed magnetic layer 25 of the first fixed magnetic layer 27 in the range of 10 to 70 (Å Tesla) And the first pinned magnetic layer 2
It is preferable that the absolute value obtained by subtracting the magnetic film thickness Ms · t _P2 of the second fixed magnetic layer 25 from the magnetic film thickness Ms · t _{P1 of} 7 is 2 (angstrom · tesla) or more.

Also, (magnetic film thickness Ms · t _{P1 of} first fixed magnetic layer 27) / (magnetic film thickness M of second fixed magnetic layer 25)
s · t _P2 ) is 0.53 to 0.95, or 1.05
More preferably, it is within the range of 1.8 to 1.8. The magnetic thickness M of the first fixed magnetic layer 27 is within the above range.
s · t _P1 and the magnetic film thickness Ms · t of the second pinned magnetic layer 25
_P2 is in the range of 10 to 50 (angstrom tesla), and the magnetic film thickness Ms · t _{P1 of} the first fixed magnetic layer 27 to the magnetic film thickness Ms of the second fixed magnetic layer 25
It is preferable that the absolute value obtained by subtracting t _P2 is not less than 2 (angstrom tesla).

Next, the nonmagnetic intermediate layer 26 interposed between the first fixed magnetic layer 27 and the second fixed magnetic layer 25 shown in FIG.
Is preferably formed of one or more alloys of Ru, Rh, Ir, Cr, Re, and Cu. In the present invention, as shown in FIG. 3, when the antiferromagnetic layer 28 is formed above the free magnetic layer 21, the nonmagnetic intermediate layer 26 has a thickness of 2.5 to 6.4 angstroms. Alternatively, it is preferably within the range of 6.6 to 10.7 angstroms. Within this range, the exchange coupling magnetic field (Hex) of at least 500 (Oe) or more
Can be obtained.

In the present invention, the thickness of the nonmagnetic intermediate layer 26 is more preferably in the range of 2.8 to 6.2 angstroms, or 6.8 to 10.3 angstroms. Within this range, at least 10
It is possible to obtain an exchange coupling magnetic field of 00 (Oe) or more. If the antiferromagnetic layer 28 is formed with at least 90 angstroms or more, an exchange coupling magnetic field of 500 (Oe) or more can be obtained. The film thickness is set to 1
If it is more than 00 Å, 1000 (Oe)
The above exchange coupling magnetic field can be obtained.

In the spin-valve thin film device shown in FIG.
The thickness t _P1 of the first pinned magnetic layer 27 is formed to be different from the thickness t _{P2 of} the second pinned magnetic layer 25.
The thickness t _P1 of the fixed magnetic layer 27 is formed larger than the thickness t _{P2 of} the second fixed magnetic layer 25. Further, the magnetization of the first pinned magnetic layer 27 is magnetized in the illustrated Y direction,
The magnetization of the second fixed magnetic layer 25 is magnetized in a direction opposite to the Y direction in the drawing, and the magnetizations of the first fixed magnetic layer 27 and the second fixed magnetic layer 25 are in a ferri-state. A method for controlling the magnetization directions of the first fixed magnetic layer 27 and the second fixed magnetic layer 25 shown in FIG. 3 will be described below.

First, each layer shown in FIG. 3 is formed by a sputtering method or the like, and in a process after the film formation, annealing (heat treatment) in a magnetic field is performed. Ms · t _{P1 of} the first pinned magnetic layer 27
(Magnetic moment) is Ms · of the second pinned magnetic layer 25.
If it is larger than t _P2 (magnetic moment), the direction of magnetization of the first fixed magnetic layer 27 is set to 100 to 1 in a desired direction.
A magnetic field of 000 (Oe) or 5 k (Oe) may be applied. As shown in FIG. 3, when the first pinned magnetic layer 27 having a large Ms · t _P1 is to be oriented in the illustrated Y direction, referring to Table 1 described above, 100 to 1 in the illustrated Y direction.
A magnetic field of k (Oe) (see Table 1 (2)) or 5 k (Oe) or more (see Table 1 (3)) in the Y direction in the drawing is applied during the heat treatment.

By applying a magnetic field of 100 to 1 k (Oe) in the Y direction in the drawing, the magnetization of the first fixed magnetic layer 27 having a large Ms · t _P1 is oriented in the Y direction in the drawing, and the second fixed magnetic layer 25 is turned on. Magnetization tends to be in an antiparallel state. The magnetization of the first pinned magnetic layer 27 is fixed in the Y direction in the figure by an exchange coupling magnetic field (exchange anisotropic magnetic field) generated at the interface between the first pinned magnetic layer 27 and the antiferromagnetic layer 28. And
Thereby, the magnetization of the second fixed magnetic layer 25 is fixed in the direction opposite to the Y direction in the drawing.

When a magnetic field of 5 k (Oe) or more is applied in the Y direction in the figure, a magnetic field larger than the exchange coupling magnetic field (RKKY interaction) generated between the first fixed magnetic layer 27 and the second fixed magnetic layer 25 is generated. Is applied, both the magnetizations of the first fixed magnetic layer 27 and the second fixed magnetic layer 25 are magnetized in the Y direction in the drawing, and the magnetization of the first fixed magnetic layer 27 becomes the antiferromagnetic layer 28. Is fixed in the Y direction in the figure by an exchange coupling magnetic field (exchange anisotropic magnetic field) generated at the interface with.
On the other hand, the magnetization of the second pinned magnetic layer 25 is reversed by the exchange coupling magnetic field (RKKY interaction) with the first pinned magnetic layer 27 by removing the applied magnetic field, and the magnetization of the first pinned magnetic layer 27 is removed. It becomes antiparallel to the magnetization and is fixed.

Alternatively, when the magnetic moment of the first pinned magnetic layer 27 is smaller than the magnetic moment of the second pinned magnetic layer 25, the direction of the magnetization of the first pinned magnetic layer 27 is reversed. A magnetic field of 100 to 1000 (Oe) is applied, or a magnetic field of 5 k (Oe) or more is applied in a direction in which magnetization is desired.

As shown in FIG. 4, on both sides of the laminated body from the underlayer 10 to the protective layer 29, the hard bias layers
30 and the conductive layer 131 are formed, and the hard bias layer 130 is magnetized in the X direction in the drawing, so that the magnetization of the free magnetic layer 21 is aligned in the X direction in the drawing.

FIG. 5 is a cross-sectional view schematically showing the structure of a spin-valve thin film element according to a third embodiment of the present invention.
FIG. 6 is a cross-sectional view of the spin-valve thin film element shown in FIG. 5 as viewed from a surface facing a recording medium. This spin-valve thin-film element is a so-called dual spin-valve thin-film element in which a nonmagnetic conductive layer, a pinned magnetic layer, and an antiferromagnetic layer are formed one by one above and below a free magnetic layer. In this dual spin-valve thin-film element, a large ΔMR can be expected as compared with a single spin-valve thin-film element because there are two combinations of these three layers of a free magnetic layer / non-magnetic conductive layer / fixed magnetic layer. It is compatible with density recording.

The spin-valve thin film element shown in FIG. 5 has an underlayer 30, an antiferromagnetic layer 31, a first fixed magnetic layer (lower) 32, a nonmagnetic intermediate layer (lower) 33, and a second fixed layer. Magnetic layer (lower) 34, non-magnetic conductive layer 35, free magnetic layer 36
(Reference numerals 37 and 39 are Co films, reference numeral 38 is a NiFe alloy film), a nonmagnetic conductive layer 40, and a second fixed magnetic layer (upper) 4
1. Non-magnetic intermediate layer (upper) 42, first fixed magnetic layer (upper)
43, an antiferromagnetic layer 44, and a protective layer 45 are stacked in this order. As shown in FIG. 6, the hard bias layers 130 are provided on both sides of the stacked body from the underlayer 30 to the protective layer 45.
And a conductive layer 131 are formed.

The antiferromagnetic layers 31 and 44 of the spin-valve thin-film element shown in FIG. 5 are preferably formed of a PtMn alloy, or are replaced with XM
n (where X is one of Pd, Ir, Rh, and Ru)
Or two or more elements) alloys or Pt
-Mn-X '(where X' is Pd, Ir, Rh, R
u, Au, or Ag).

Also in this spin-valve type thin film element,
Said first and thickness t _P1 of the fixed magnetic layer (lower) 32, the thickness ratio between the film thickness t _P2 of the second pinned magnetic layer (lower) 34, and first
Thickness ratio between the film thickness t _P2 of the fixed magnetic layer (upper) 43 and the film thickness t _P1 of the second pinned magnetic layer 41 (top) (first film thickness t _P1 of the fixed magnetic layer) / (a 2 has a thickness t _P2 ) of 0.3.
It is preferably in the range of 33 to 0.95, or 1.05 to 4. Further, the film thickness ratio is within the above range, and the film thickness t of the first pinned magnetic layers (lower) 32 and (upper) 43 is
The thickness t _{P2 of P1} and the second pinned magnetic layers (lower) 34 and (upper) 41 is in the range of 10 to 70 Å, and the thickness t _{P1 of} the first fixed magnetic layers 32 and 43 is the second If the absolute value obtained by subtracting the thickness t _P2 of the fixed magnetic layers 34 and 41 is 2 Å or more, an exchange coupling magnetic field of 500 (Oe) or more can be obtained.

In the present invention, (the thickness t _{P1 of} the first fixed magnetic layer) / (the thickness t _{P2 of} the second fixed magnetic layer) is 0.5
It is more preferably in the range of 3 to 0.95, or 1.05 to 1.8. Further, the film thickness t _P1 and the second The thickness t _P2 of the fixed magnetic layers (lower) 34 and (upper) 41 is in the range of 10 to 50 Å, and the first fixed magnetic layer 32,
If the absolute value obtained by subtracting the film thickness t _P2 of the second pinned magnetic layers 34 and 41 from the film thickness t _{P1 of} 43 is 2 Å or more, an exchange coupling magnetic field of 1000 (Oe) or more can be obtained.

Incidentally, the film thickness t _{P1 of} the first pinned magnetic layer (lower) 32 formed below the free magnetic layer 36.
_Is larger than the thickness t _{P2 of} the second pinned magnetic layer (lower) 34, the thickness t _{P1 of} the first pinned magnetic layer (lower) 32
It has been experimentally confirmed that when the difference in film thickness between the second fixed magnetic layer (lower) 34 and the second fixed magnetic layer (lower) 34 is about 6 Å or less, the exchange coupling magnetic field tends to decrease. This phenomenon is caused by, for example, a PtMn alloy that requires heat treatment to generate an exchange coupling magnetic field (exchange anisotropic magnetic field) at the interface with the first pinned magnetic layers (lower) 32 and (upper) 43. This is seen when the antiferromagnetic layers 31 and 44 are used.

The decrease in the exchange coupling magnetic field is caused by the free magnetic layer 36.
Due to the thermal diffusion between the antiferromagnetic layer 31 and the first pinned magnetic layer (lower) 32 formed below, the magnetic film thickness of the first pinned magnetic layer (lower) 32 decreases. And the first
This is because the magnetic film thickness of the fixed magnetic layer (lower) 32 and the film thickness t _{P2 of} the second fixed magnetic layer 34 are substantially the same. Therefore, in the present invention, the first fixed magnetic layer (upper)
Film thickness t _{P1 of} 43 / film thickness t of second pinned magnetic layer (upper) 41
_P2 ), the film thickness t _P1 / (first fixed magnetic layer (lower) 32)
It is preferable to increase the thickness t _P2 ) of the second pinned magnetic layer (lower) 34.

The generation of the heat diffusion layer is not limited to the dual spin-valve thin-film element shown in FIG. (See FIG. 1).

As described above, the first pinned magnetic layer (lower)
32, (top) 43 magnetic film thickness Ms · t _P1 and the second fixed magnetic layer (lower) 34, the magnetic film thickness Ms · t _P2 (upper) 41
If there is no difference between the first fixed magnetic layers (lower) 32 and (upper) 43
Thickness Ms · t _P1 and second fixed magnetic layer (lower) 3
If the difference between the magnetic film thicknesses Ms · t _P2 of the fourth and upper 41 becomes too large, the exchange coupling magnetic field is lowered, which is not preferable. Therefore, in the present invention, the first fixed magnetic layer (lower) 32,
(Upper) film thickness t _{P1 of} 43 and second pinned magnetic layer (lower) 34,
In the same manner as the film thickness ratio of the film thickness t _P2 of (upper) 41, the magnetic film thickness Ms of the first pinned magnetic layer (lower) 32 and (upper) 43.
t _P1 ) / (Magnetic film thickness Ms · t _{P2 of} the second fixed magnetic layer (lower) 34 and (upper) 41) is in the range of 0.33 to 0.95 or 1.05 to 4. It is preferred that In the present invention, the first pinned magnetic layers (lower) 32, (upper) 4
No. 3 magnetic film thickness Ms · t _P1 and second pinned magnetic layer (bottom)
34, (upper) 41, the magnetic film thickness Ms · t _P2 is 10-70.
(Angstrom tesla) and the magnetic film thickness Ms of the first pinned magnetic layers (lower) 32 and (upper) 43.
It is preferable that the absolute value obtained by subtracting the magnetic film thickness Ms · t _P2 of the second fixed magnetic layers (lower) 34 and (upper) 41 from t _P1 is 2 (angstroms · tesla) or more.

The first fixed magnetic layer (lower) 32,
(Top) Magnetic film thickness Ms · t _{P1 of} 43 / (Second pinned magnetic layer (bottom) 34, Magnetic film thickness of (top) 41 Ms · t _P2 )
Is more preferably in the range of 0.53 to 0.95, or 1.05 to 1.8. Also, within the above range, the magnetic film thickness Ms · t _{P1 of} the first fixed magnetic layer (lower) 32 and (upper) 43 and the second fixed magnetic layer (lower) 34,
(Upper) The magnetic film thickness Ms · t _P2 of 41 is 10 to 50 for both.
(Angstrom tesla), and from the magnetic film thickness Ms · t _{P1 of} the first fixed magnetic layer (lower) 32 and (upper) 43, the second fixed magnetic layer (lower) 34, (upper) ) 4
It is preferable that the absolute value obtained by subtracting the magnetic film thickness Ms · t _P2 from 1 be 2 (angstrom tesla) or more.

Next, the first pinned magnetic layer (lower) 3 shown in FIG.
2, (upper) 43 and second pinned magnetic layer (lower) 34, (upper)
The non-magnetic intermediate layers 33 and 42 interposed between R
It is preferable to be formed of one or more alloys of u, Rh, Ir, Cr, Re, and Cu. FIG.
As shown in (3), the thickness of the nonmagnetic intermediate layer (lower) 33 formed below the free magnetic layer 36 is 3.6 to 9.6.
Preferably, it is formed in the range of Å. Within this range, an exchange coupling magnetic field (Hex) of 500 (Oe) or more can be obtained. The non-magnetic intermediate layer (lower) 33 is more preferably formed in a range of 4 to 9.4 angstroms, since an exchange coupling magnetic field of 1000 (Oe) or more can be obtained.

In the present invention, as shown in FIG. 5, the nonmagnetic intermediate layer (upper) formed above the free magnetic layer 36
The film thickness of 42 is preferably in the range of 2.5 to 6.4 angstroms, or 6.8 to 10.7 angstroms. Within this range, at least 50
An exchange coupling magnetic field (Hex) of 0 (Oe) or more can be obtained. In the present invention, the non-magnetic intermediate layer (upper) 42
Is more preferably in the range of 2.8 to 6.2 angstroms, or 6.8 to 10.3 angstroms. Within this range, at least 10
It is possible to obtain an exchange coupling magnetic field of 00 (Oe) or more.

If the antiferromagnetic layers 31 and 44 are formed with at least 100 angstroms or more, 500
It is possible to obtain an exchange coupling magnetic field of (Oe) or more.
If the film thickness is set to 110 Å or more,
It is possible to obtain an exchange coupling magnetic field of 1000 (Oe) or more. Conventionally, the thicknesses of the antiferromagnetic layers 31 and 44 have been formed at about 200 Å or more.
According to the present invention, the antiferromagnetic layers 31 and
44 can be formed. In particular, in the case of a dual spin-valve thin film element, two antiferromagnetic layers 31 and 44 are formed. Can be reduced by about 200 angstroms or more. In the spin-valve thin film element formed as described above, the gap length Gl can be reduced even if the lower gap layer 121 and the upper gap layer 125 shown in FIG. It is capable of responding to high-density recording.

The first pinned magnetic layer (lower) 32, (upper)
43 and the thickness of the second pinned magnetic layers (lower) 34 and (upper) 41, the thicknesses of the nonmagnetic intermediate layers (lower) 33 and (upper) 42, and the antiferromagnetic layers 31 and 42. By appropriately adjusting the thickness of the film 44 within the above-described range, it is possible to maintain the same ΔMR as that of the related art, and specifically, it is possible to obtain a ΔMR of about 10% or more.

As shown in FIG. 5, the thickness t _P1 of the first pinned magnetic layer (lower) 32 formed below the free magnetic layer 36 is formed via the non-magnetic intermediate layer 33. The second pinned magnetic layer (lower) 34 is formed to be thinner than the film thickness t _P2 . On the other hand, the thickness t _P1 of the first pinned magnetic layer (upper) 43 formed above the free magnetic layer 36 is equal to the thickness of the second pinned magnetic layer 41 formed via the nonmagnetic intermediate layer 42.
It is formed thicker than the film thickness t _P2 of (upper). And
The magnetizations of the first fixed magnetic layers (lower) 32 and (upper) 43 are both magnetized in the direction opposite to the Y direction in the figure, and the magnetizations of the second fixed magnetic layers (lower) 34 and (upper) 41 are shown in the figure. It is magnetized in the Y direction. In the case of the single spin-valve type thin film element shown in FIGS. 1 and 3, Ms · t _P2 of the Ms · t _P1 of the first pinned magnetic layer a second pinned magnetic layer is differently thickness etc. Is adjusted, and the magnetization direction of the first pinned magnetic layer may be either the illustrated Y direction or the opposite direction to the illustrated Y direction.

However, in the dual spin-valve thin film element shown in FIG. 5, the first pinned magnetic layer (lower) 32,
It is necessary that both (upper) 43 magnetizations be directed in the same direction. For this reason, in the present invention, the first fixed magnetic layers (lower) 32 and the (upper) 43 magnetic moment Ms · t
And _P1, the second pinned magnetic layer (lower) 34, are adjusted (upper) 41 Adjustment of the magnetic moment Ms · t _P2, and the direction and magnitude of the magnetic field applied during the heat treatment properly. Here, the magnetizations of the first fixed magnetic layers (lower) 32 and (upper) 43 are both oriented in the same direction because the magnetizations of the first fixed magnetic layers (lower) 32 and (upper) 43 are different from the magnetizations of the first fixed magnetic layers (lower) 32 and (upper) 43. This is to keep the magnetizations of the antiparallel second fixed magnetic layers (lower) 34 and (upper) 41 in the same direction, and the reason will be described below.

As described above, the ΔMR of the spin-valve thin film element is obtained from the relationship between the fixed magnetization of the fixed magnetic layer and the variable magnetization of the free magnetic layer. When divided into two layers, the first fixed magnetic layer and the second fixed magnetic layer, the layer of the fixed magnetic layer directly involved in the ΔMR is the second fixed magnetic layer, and The fixed magnetic layer plays a so-called auxiliary role for fixing the magnetization of the second fixed magnetic layer in a certain direction.

The second pinned magnetic layer (lower) 3 shown in FIG.
Assuming that the magnetizations of the upper and lower layers 41 and 41 are fixed in opposite directions, for example, the resistance is large in the relationship between the fixed magnetization of the second fixed magnetic layer (upper) 41 and the variable magnetization of the free magnetic layer 36. Even so, the resistance becomes very small in the relationship between the fixed magnetization of the second fixed magnetic layer (lower) 34 and the fluctuating magnetization of the free magnetic layer 36, and as a result, ΔMR in the dual spin-valve thin film element becomes 1 and 3 are smaller than the ΔMR of the single spin-valve thin film element.

This problem is not limited to the dual spin-valve thin film element in which the fixed magnetic layer is divided into two layers via the non-magnetic intermediate layer as in the present invention. Is the same as
In order to exhibit the characteristics of a dual spin-valve thin-film device that can increase ΔMR and obtain a large output compared to a single spin-valve thin-film device, the fixed magnetic layers formed above and below the free magnetic layer must be in the same direction. Must be fixed to

According to the present invention, as shown in FIG.
The pinned magnetic layer formed below the free magnetic layer 36 is such that Ms · t _P2 of the second pinned magnetic layer (lower) 34 is
The magnetization of the second fixed magnetic layer (lower) 34, which is larger than Ms · t _P1 of the first fixed magnetic layer (lower) 32 and has a larger Ms · t _P2 , is fixed in the Y direction in the figure. Here, the so-called synthetic magnetic moment obtained by adding Ms · t _{P2 of} the second fixed magnetic layer 34 and Ms · t _{P1 of} the first fixed magnetic layer 32 is a second magnetic moment having a large Ms · t _P2. It is governed by the magnetic moment of the fixed magnetic layer 34 and is directed in the Y direction in the figure.

On the other hand, the pinned magnetic layer formed above the free magnetic layer 36 is the M pin of the first pinned magnetic layer (top) 43.
s · t _P1 is the Ms · t of the second pinned magnetic layer (upper) 41.
The magnetization of the first fixed magnetic layer (upper) 43, which is larger than t _P2 and has a larger Ms · t _P1 , is fixed in the direction opposite to the Y direction in the figure. M of the first pinned magnetic layer (upper) 43
s · t _P1 and Ms · t _{P2 of} the second pinned magnetic layer (upper) 41
The so-called combined magnetic moment is controlled by Ms · t _P1 of the first pinned magnetic layer (upper) 43 and directed in the direction opposite to the Y direction in the figure.

That is, in the dual spin-valve thin film element shown in FIG. 5, Ms · t _{P1 of} the first fixed magnetic layer and Ms · t _P of the second fixed magnetic layer above and below the free magnetic layer 36.
The direction of the resultant magnetic moment that can be obtained by adding _P2 is in the opposite direction. Therefore, the combined magnetic moment formed below the free magnetic layer 36 in the illustrated Y direction and the combined magnetic moment formed above the free magnetic layer 36 in the opposite direction to the illustrated Y direction. The moment forms a leftward magnetic field in the figure. Therefore, the first fixed magnetic layers (lower) 32 and (upper) 4 are caused by the magnetic field formed by the resultant magnetic moment.
The magnetization of No. 3 and the magnetizations of the second fixed magnetic layers (lower) 34 and (upper) 41 can maintain a more stable ferri-state.

Further, the sense current 114 mainly flows around the nonmagnetic conductive layers 35 and 39 having a small specific resistance, and the sense current 114 is caused to flow to form a sense current magnetic field according to the right-hand rule. However, by flowing the sense current 114 in the direction of FIG.
6, the direction of the sense current magnetic field generated by the sense current at the location of the first fixed magnetic layer (lower) 32 / non-magnetic intermediate layer (lower) 33 / second fixed magnetic layer (lower) 34 The first fixed magnetic layer (lower) 32 / the non-magnetic intermediate layer (lower) 33
/ The direction of the synthetic magnetic moment of the second pinned magnetic layer (lower) 34 can be matched with the direction of the free magnetic layer 3.
First fixed magnetic layer (upper) 43 formed above layer 6
/ Non-magnetic intermediate layer (upper) 42 / second fixed magnetic layer (upper) 4
The first fixed magnetic layer (upper) 43 / non-magnetic intermediate layer (upper) 42 /
The direction of the combined magnetic moment of the second pinned magnetic layer (upper) 41 can be matched.

The merit of making the direction of the sense current magnetic field coincide with the direction of the resultant magnetic moment will be described later in detail. Since a large sense current can be passed, there is a very great merit that the reproduction output can be improved. The relationship between the sense current magnetic field and the direction of the combined magnetic moment is because the combined magnetic moment of the fixed magnetic layers formed above and below the free magnetic layer 36 forms a leftward magnetic field in the drawing.

The environmental temperature in the apparatus rises to about 200 ° C., and the environmental temperature tends to further increase in the future due to an increase in the number of rotations of the recording medium, an increase in sense current, and the like. As the environmental temperature increases, the exchange coupling magnetic field decreases. However, according to the present invention, the first fixed magnetic field is thermally stabilized by the magnetic field formed by the combined magnetic moment and the sense current magnetic field. The magnetizations of the layers (lower) 32 and (upper) 43 and the magnetizations of the second pinned magnetic layers (lower) 34 and (upper) 41 can be maintained in a ferri-state.

The above-described formation of the magnetic field by the combined magnetic moment, and the directional relationship between the magnetic field by the combined magnetic moment and the sense current magnetic field are unique to the present invention. Moreover, the conventional dual spin-valve thin film element having a fixed magnetic layer oriented in the same direction and fixedly magnetized cannot be obtained.

Next, the direction and magnitude of the magnetic field applied during the heat treatment will be described below. In the spin-valve thin film element shown in FIG.
In order to generate an exchange coupling magnetic field (exchange anisotropic magnetic field) at the interface with the first pinned magnetic layers (lower) 32 and (upper) 43 such as an alloy, an antiferromagnetic material requiring heat treatment is used. Therefore, unless the direction and magnitude of the magnetic field applied during the heat treatment are properly controlled, the first pinned magnetic layer (lower) 32,
(Upper) 43 and second pinned magnetic layer (lower) 34, (upper) 41
Cannot be obtained in the direction as shown in FIG.

First, at the stage of film formation, as shown in FIG.
Ms · t _P1 of the first fixed magnetic layer (lower) 32 formed below the free magnetic layer 36 is smaller than Ms · t _{P2 of} the second fixed magnetic layer (lower) 34, and The Ms · t _P1 of the first fixed magnetic layer (upper) 43 formed above the free magnetic layer 36 is changed to the second fixed magnetic layer (upper) 41.
Ms · t _P2 . As shown in FIG. 5, when the first pinned magnetic layers (lower) 32 and (upper) 43 are desired to be directed in the directions opposite to the Y direction shown in FIG. It is necessary to apply a magnetic field of 5 k (Oe) or more (see Tables 1 (4) and 2 (4)) in the direction opposite to the direction.

By applying a magnetic field of 5 k (Oe) or more in the direction opposite to the Y direction in the figure, the first fixed magnetic layer (lower)
32, (upper) 43 magnetization and second pinned magnetic layer (lower) 3
4, the magnetization of (upper) 41 is once directed in the direction opposite to the Y direction in the figure. The first fixed magnetic layer (lower) 32, (upper) 4
No. 3 is fixed in the direction opposite to the Y direction in the figure by an exchange coupling magnetic field (exchange anisotropic magnetic field) at the interface with the antiferromagnetic layers 31 and 44, and removes a magnetic field of 5 k (Oe) or more to remove the magnetic field. The magnetizations of the second fixed magnetic layers (lower) 34 and (upper) 41 are reversed in the Y direction in the figure by an exchange coupling magnetic field (RKKY interaction) with the first fixed magnetic layers (lower) 32 and (upper) 43. Then, it is fixed in the illustrated Y direction.

Alternatively, a magnetic field of 5 k (Oe) or more is applied as shown in FIG.
It may be given in the direction. In this case, the magnetizations of the first fixed magnetic layers (lower) 32 and (upper) 43 and the magnetizations of the second fixed magnetic layers (lower) 34 and (upper) 41 are opposite to the magnetization directions shown in FIG. To form a magnetic field due to the clockwise resultant magnetic moment.

In the present invention, the first fixed magnetic layer (lower) 32 formed below the free magnetic layer 36 has a Ms ·
t _P1 is set to be larger than Ms · t _{P2 of} the second pinned magnetic layer 34 and Ms · t _P1 of the first pinned magnetic layer 43 formed above the free magnetic layer 36 is set to the second value. May be smaller than Ms · t _P2 of the fixed magnetic layer 41 described above. Also in this case, the first pinned magnetic layers (lower) 32, (upper) 4
By applying a magnetic field of 5 k (Oe) or more in the direction in which the magnetization No. 3 is to be obtained, that is, in the illustrated Y direction or in the opposite direction to the illustrated Y direction, the second fixed magnetic layer ( The lower) 34 and the (upper) 41 can be fixed in the same direction, and a magnetic field can be formed by a combined clockwise or counterclockwise magnetic moment.

The second pinned magnetic layer (lower) 3 formed above and below the free magnetic layer 36 by a method other than the method described above.
It is not possible to direct the magnetizations of the fourth and upper 41 in the same direction and to form a magnetic field by the combined magnetic moment and to form a directional relationship between the magnetic field by the combined magnetic moment and the sense current magnetic field.

In the present invention, the following method is used.
Although the magnetizations of the second pinned magnetic layers (lower) 34 and (upper) 41 can be directed in the same direction, the combined magnetic moments formed above and below the free magnetic layer 36 are directed in the same direction. However, a magnetic field cannot be formed by the combined magnetic moment. However, with the dual spin-valve thin film element of the present invention, it is possible to obtain the same ΔMR as that of the conventional dual spin-valve thin film element by the following heat treatment method. As compared with the above, the magnetization states of the fixed magnetic layers (the first fixed magnetic layer and the second fixed magnetic layer) can be kept thermally stable.

First, Ms · t _{P1 of} the first fixed magnetic layer (lower) 32 formed below the free magnetic layer 36 and the first fixed magnetic layer (above the free magnetic layer 36) When the Ms · t _P1 of the upper (43) is larger than the Ms · t _{P2 of} the second fixed magnetic layer (the lower) 34 and (upper) 41, the first fixed magnetic layer (the lower) 32 , (Top) 4
By applying a magnetic field of 100 to 1 k (Oe) or 5 k (Oe) or more in the direction in which the magnetization of No. 3 is to be directed, the first pinned magnetic layers (lower) 32 and (upper) 43 are in the same direction. , The first pinned magnetic layer (bottom) 32, (top)
By the exchange coupling magnetic field (RKKY interaction) with 43,
The second fixed magnetic layer (lower) 34, which is magnetized in antiparallel to the magnetization of the first fixed magnetic layer (lower) 32 and (upper) 43,
(Upper) The magnetizations of 41 can be fixed in the same direction.

Alternatively, Ms · t _{P1 of} the first fixed magnetic layer (lower) 32 formed below the free magnetic layer 36 and the first fixed magnetic layer (above the free magnetic layer 36) When the Ms · t _P1 of the upper 43 is smaller than the Ms · t _{P2 of} the second fixed magnetic layer (lower) 34 and the (upper) 41, the first fixed magnetic layer (lower) 32 , (Top) 4
100-100k in the direction opposite to the direction of magnetization
(Oe) or the first fixed magnetic layer (lower) 3
By applying a magnetic field of 5 k (Oe) or more in the direction in which the magnetization of 2, (upper) 43 is to be directed, the first fixed magnetic layer (lower)
32 and (upper) 43 are directed in the same direction, and the exchange coupling magnetic field (R) with the first pinned magnetic layers (lower) 32 and
Due to the KKY interaction), the magnetizations of the second fixed magnetic layers (lower) 34 and (upper) 41 which are magnetized in antiparallel to the magnetizations of the first fixed magnetic layers (lower) 32 and (upper) 43 are both changed. It can be fixed in the same direction.

As described above, according to the spin-valve thin-film element shown in FIGS. 1 to 6, the fixed magnetic layer is divided into two layers of the first fixed magnetic layer and the second fixed magnetic layer via the non-magnetic intermediate layer. And the magnetization of the two fixed magnetic layers is changed to an anti-parallel state (ferri state) by an exchange coupling magnetic field (RKKY interaction) generated between the two fixed magnetic layers. The stable magnetization state of the pinned magnetic layer can be maintained.

In particular, in the present invention, a PtMn alloy having a very high blocking temperature and generating a large exchange coupling magnetic field (exchange anisotropic magnetic field) at the interface with the first pinned magnetic layer is used as the antiferromagnetic layer. Thereby, the magnetization states of the first pinned magnetic layer and the second pinned magnetic layer can be made more excellent in thermal stability.

In the present invention, the first pinned magnetic layer and the second
And the thickness of the non-magnetic intermediate layer interposed between the first fixed magnetic layer and the second fixed magnetic layer,
By forming the thickness of the antiferromagnetic layer within an appropriate range, the exchange coupling magnetic field (Hex) can be increased, and therefore, the heat of the fixed magnetization of the first fixed magnetic layer and the second fixed magnetic layer can be increased. It is possible to further improve the target stability.

The thickness ratio of the thickness t _P1 of the first pinned magnetic layer to the thickness t _{P2 of} the second pinned magnetic layer,
By forming the thicknesses of the fixed magnetic layer, the second fixed magnetic layer, the nonmagnetic intermediate layer, and the antiferromagnetic layer within appropriate ranges, it is possible to obtain a ΔMR that is almost the same as that of the related art. .

Further, in the present invention, Pt is used as the antiferromagnetic layer.
When using an antiferromagnetic material that requires heat treatment to generate an exchange coupling magnetic field (exchange anisotropic magnetic field) at the interface with the first fixed magnetic layer, such as a Mn alloy, the first fixed magnetic layer Ms · t _P1 of the second pinned magnetic layer and Ms · t _{P2 of} the second pinned magnetic layer are formed with different values, and the magnitude and direction of the applied magnetic field during the heat treatment are appropriately adjusted, thereby obtaining the first pinned magnetic layer. The magnetization of the magnetic layer (and the second pinned magnetic layer) can be magnetized in a direction in which the magnetization is to be obtained.

In particular, in the dual spin-valve thin film element shown in FIG. 5, the first pinned magnetic layer (lower) 32,
(Top) 43 Ms · t _P1 and second pinned magnetic layer (bottom) 3
4, (upper) 41, by appropriately adjusting the Ms · t _P2, and by appropriately adjusting the magnitude and direction of the applied magnetic field during the heat treatment, the upper and lower free magnetic layers 36 involved in ΔMR are formed. Two second fixed magnetic layers (lower) 34,
(Upper) Since the magnetization of both 41 can be fixed in the same direction and the combined magnetic moments formed above and below the free magnetic layer 36 can be formed in opposite directions, the formation of a magnetic field by the combined magnetic moment and the combination The directional relationship between the magnetic field due to the magnetic moment and the sense current magnetic field can be formed, and the thermal stability of magnetization of the fixed magnetic layer can be further improved.

FIG. 7 is a cross-sectional view schematically showing the structure of a spin-valve thin film element according to a fourth embodiment of the present invention.
FIG. 8 is a cross-sectional view of the spin-valve thin film element shown in FIG. 7 when viewed from a surface facing a recording medium. Also in this spin-valve thin-film element, similarly to the spin-valve thin-film element shown in FIGS. It detects a magnetic field. The moving direction of the magnetic recording medium such as a hard disk is the Z direction in the figure, and the direction of the leakage magnetic field from the magnetic recording medium is the Y direction. In this spin-valve thin film element, not only the fixed magnetic layer but also the free magnetic layer is divided into two layers, a first free magnetic layer and a second free magnetic layer, via a nonmagnetic intermediate layer.

As shown in FIG. 7 and FIG.
The antiferromagnetic layer 51, the first fixed magnetic layer 52, the nonmagnetic intermediate layer 53, the second fixed magnetic layer 54, the nonmagnetic conductive layer 55, the first
, A non-magnetic intermediate layer 59, a second free magnetic layer 60, and a protective layer 61 in this order. The underlayer 50 and the protective layer 61 are formed of, for example, Ta. Preferably, the antiferromagnetic layer 51 is formed of a PtMn alloy. PtMn alloys include NiMn alloys and Fn alloys conventionally used as antiferromagnetic layers.
It has better corrosion resistance than eMn alloys, etc., and also has a higher blocking temperature and a larger exchange coupling magnetic field. In the present invention, instead of the PtMn alloy, X—Mn (where X
Is one or more of Pd, Ir, Rh, and Ru) alloys, or Pt—Mn—X ′
(Where X 'is Pd, Ir, Rh, Ru, Au, Ag
Alloys of any one or two or more) may be used.

The first fixed magnetic layer 52 and the second fixed magnetic layer 54 are formed of a Co film, a NiFe alloy, a CoFe alloy, a CoNiFe alloy, or the like. The nonmagnetic intermediate layer 53 is made of Ru, Rh, Ir, Cr, Re, Cu
It is preferable to be formed of one or more alloys among them. Further, the nonmagnetic conductive layer 55 is formed of Cu or the like.

The magnetization of the first fixed magnetic layer 52 and the magnetization of the second fixed magnetic layer 54 are in a ferri state in which they are magnetized antiparallel to each other. For example, the magnetization of the first fixed magnetic layer 52 is In the illustrated Y direction, the magnetization of the second pinned magnetic layer 54 is fixed in a direction opposite to the illustrated Y direction. In order to maintain the stability of the ferri state, a large exchange coupling magnetic field is required. In the present invention, various optimizations described below are performed to obtain a larger exchange coupling magnetic field.

In the spin-valve thin-film element shown in FIGS. 7 and 8, (thickness t _{P1 of} first fixed magnetic layer 52) / (thickness t _{P2 of} second fixed magnetic layer 54) is 0.33. To 0.95 or 1.05 to 4, more preferably 0.53 to 0.95 or 1.08.
１1.8.

The thickness of each of the first fixed magnetic layer 52 and the second fixed magnetic layer 54 is 10 to 70 angstroms, and | the thickness t _{P1 of} the first fixed magnetic layer 52.
It is preferable that the thickness t _P2 | ≧ 2 angstroms of the second pinned magnetic layer 54, and more preferably, 10 to 50
Angstrom and | thickness t _{P1 of} first fixed magnetic layer 52 -thickness t _{P2 of} second fixed magnetic layer 54 | ≧ 2 angstroms.

As described above, if there is no difference between the magnetic film thickness Ms · _tp1 of the first fixed magnetic layer 52 and the magnetic film thickness Ms · _tp2 of the second fixed magnetic layer 54, the magnetization state Is less likely to be in a ferri-state, and even if the difference between the magnetic film thickness Ms · _tp1 of the first fixed magnetic layer 52 and the magnetic film thickness Ms · _tp2 of the second fixed magnetic layer 54 becomes too large. This leads to a decrease in exchange coupling magnetic field, which is not preferable. Therefore, in the present invention, the thickness t _{p1 of} the first pinned magnetic layer 52 and the second pinned magnetic layer 54
As with the thickness ratio of the thickness t _p2 of, (the magnetic film thickness Ms · t _p1 of the first pinned magnetic layer 52) / (the magnetic film thickness Ms · t of the second pinned magnetic layer 54 _p2 ) is from 0.33 to 0.9
It is preferably 5 or in the range of 1.05 to 4. In the present invention, the magnetic film thickness Ms · t _p2 of the first magnetic film thickness Ms · t _p1 and the second fixed magnetic layer 54 of the pinned magnetic layer 52 is 10 to 70 (Å Tesla)
And the magnetic film thickness M of the first pinned magnetic layer 52
From s · t _p1, the magnetic film thickness Ms · of the second pinned magnetic layer 54
Absolute value minus _tp2 is 2 (Angstroms / Tesla)
It is preferable that it is above.

(Magnetic film thickness Ms · t _{p1 of} first fixed magnetic layer 52) / (magnetic film thickness M of second fixed magnetic layer 54)
s · t _p2) is from 0.53 to 0.95 or 1.05,
More preferably, it is within the range of 1.8 to 1.8. The magnetic thickness M of the first fixed magnetic layer 52 is within the above range.
s · t _p1 and the magnetic film thickness Ms · t of the second pinned magnetic layer 54
_p2 are both within the range of 10 to 50 (Å Tesla), yet the magnetic film thickness Ms of the magnetic film thickness Ms · t _p1 of the first pinned magnetic layer 52 and the second pinned magnetic layer 54
It is preferable that the absolute value obtained by subtracting _tp2 is 2 (angstrom tesla) or more.

The thickness of the nonmagnetic intermediate layer 53 interposed between the first fixed magnetic layer 52 and the second fixed magnetic layer 54 is 3.6.
Preferably it is in the range of 9.6 Å. Within this range, an exchange coupling magnetic field of 500 (Oe) or more can be obtained. More preferably, 4-9.4.
It is within the range of Å, and within this range, an exchange coupling magnetic field of 1000 (Oe) or more can be obtained.

It is preferable that the thickness of the antiferromagnetic layer 51 is 90 Å or more. Within this range, an exchange coupling magnetic field of 500 (Oe) or more can be obtained. More preferably, it is 100 Å or more, and within this range, an exchange coupling magnetic field of 1000 (Oe) or more can be obtained.

On the nonmagnetic conductive layer 55 shown in FIGS. 7 and 8, a first free magnetic layer 56 is formed. FIG.
As shown in FIG. 8, the first free magnetic layer 56 is formed of two layers, and the Co film 5 is formed on the side in contact with the nonmagnetic conductive layer 55.
7 are formed. The side in contact with the nonmagnetic conductive layer 55 has C
The o film 57 is formed first to increase the ΔMR and secondly to prevent diffusion with the nonmagnetic conductive layer 55. On the Co film 57, a NiFe alloy film 58 is formed. Further, a non-magnetic intermediate layer 59 is formed on the NiFe alloy film 58. Then, a second free magnetic layer 60 is formed on the non-magnetic intermediate layer 59, and a Ta free magnetic layer 60 is formed on the second free magnetic layer 60.
A protective layer 61 is formed. The second free magnetic layer 60 includes a Co film, a NiFe alloy,
It is formed of an Fe alloy, a CoNiFe alloy, or the like.

The side surface of the spin valve film from the underlayer 50 to the protective layer 61 shown in FIG. 8 is cut into an inclined surface, and the spin valve film is formed in a trapezoidal shape. Hard bias layers 62 and 62 and conductive layers 63 and 63 are formed on both sides of the spin valve film. The hard bias layer 62 is formed of a Co—Pt alloy or a Co—Cr—Pt alloy, and the conductive layer 63 is formed of Cu or C
r or the like.

A non-magnetic intermediate layer 59 is interposed between the first free magnetic layer 56 and the second free magnetic layer 60 shown in FIGS. Exchange coupling magnetic field generated between the magnetic layers 60 (RKKY interaction)
Thereby, the magnetization of the first free magnetic layer 56 and the magnetization of the second free magnetic layer 60 are in an antiparallel state (ferri state).

In the spin valve type thin film element shown in FIG.
For example, the thickness t _F1 of the first free magnetic layer 56 is smaller than the thickness t _{F2 of} the second free magnetic layer 60. The Ms · t of the first free magnetic layer 56
_F1 is set smaller than Ms · t _{F2 of} the second free magnetic layer 60. When a bias magnetic field is applied from the hard bias layer 62 in the X direction in the drawing, the second free magnetic layer having a larger Ms · t _F2 is set. Under the influence of the bias magnetic field, the magnetization of the layer 60 is aligned in the X direction in the figure, and the exchange coupling magnetic field (RKKY interaction) with the second free magnetic layer 60 causes the first Ms · t _F1 to be small. The magnetization of the free magnetic layer 56 is aligned in the direction opposite to the X direction shown.

When an external magnetic field enters from the Y direction in the figure, the magnetizations of the first free magnetic layer 56 and the second free magnetic layer 60 rotate under the influence of the external magnetic field while maintaining a ferrimagnetic state. I do. The variable magnetization of the first free magnetic layer 56 contributing to ΔMR and the second pinned magnetic layer 54
(For example, magnetized in the opposite direction to the Y direction in the figure), the electrical resistance changes, and the signal of the external magnetic field is detected. In the present invention, the first free magnetic layer 56
Of the film thickness t _F1 of the second free magnetic layer 60 and the film thickness t _F2 of the second free magnetic layer 60 to obtain a larger exchange coupling magnetic field, and at the same time, to obtain a ΔMR that is almost the same as the conventional one. Is possible.

In the present invention, (film thickness t _{F1 of} first free magnetic layer 56 / film thickness t _{F2 of} second free magnetic layer 60)
It is preferably in the range of 0.56 to 0.83, or 1.25 to 5. Within this range, an exchange coupling magnetic field of at least 500 (Oe) or more can be obtained. Further, in the present invention, the (first free magnetic layer 56
The thickness t _{F1 of} the second free magnetic layer 60 / the thickness t _{F2 of} the second free magnetic layer 60 is
More preferably, it is in the range of 0.61 to 0.83, or 1.25 to 2.1. Within this range, an exchange coupling magnetic field of at least 1000 (Oe) can be obtained.

(The thickness t of the first free magnetic layer 56_F1
/ Film thickness t of second free magnetic layer 60 _F2) Out of 0.8
Excluding the range of 3 to 1.25 is the first free
Film thickness t of magnetic layer 56_F1And the thickness of the second free magnetic layer 60
t_F2Are formed with substantially the same value, and the first free magnetic
Ms · t of layer 56_F1And Ms of the second free magnetic layer 60
・ T_F2Are set to almost the same value, the hard bias layer
1st free current under the influence of the bias magnetic field from
The magnetization of either the magnetic layer 56 or the second free magnetic layer 60
Also tends to go in the direction of the bias magnetic field,
The magnetization of the first free magnetic layer 56 and the second free magnetic
The magnetization of the layer 60 is not in an antiparallel state, but is in a stable magnetization state.
Will be impossible to keep.

The magnetic film thickness Ms · t _{F1 of} the first free magnetic layer 56 and the magnetic film thickness M
If there is no difference in s · t _F2 to some extent, the magnetization state is unlikely to be in a ferri state, and the magnetic film thickness Ms · t _{F1 of} the first free magnetic layer 56 and the magnetic film of the second free magnetic layer 60 If the difference between the thicknesses Ms · t _F2 is too large, the exchange coupling magnetic field is undesirably reduced. Therefore, in the present invention, the first
The thickness t _F1 of the free magnetic layer 56 and the second free magnetic layer 6
In the same manner as the film thickness ratio to the film thickness t _{F2 of} 0, (the magnetic film thickness Ms · t _{F1 of} the first free magnetic layer 56) / (the magnetic film thickness Ms · of the second free magnetic layer 60) t _F2 ) is from 0.56 to
It is preferably 0.83 or within the range of 1.25 to 5. In the present invention, the first free magnetic layer 5
Magnetic film thickness Ms.t _F1 ) / (second free magnetic layer 6)
More preferably, the magnetic film thickness Ms · t _{F2 of} 0 is in the range of 0.61 to 0.83, or 1.25 to 2.1.

In the present invention, the first free magnetic layer 56
The non-magnetic intermediate layer 59 interposed between the second free magnetic layer 60 and the second free magnetic layer 60 is preferably formed of one or more alloys of Ru, Rh, Ir, Cr, Re, and Cu. . Further, the thickness of the nonmagnetic intermediate layer 59 is 5.5.
Preferably, it is in the range of １10.0 Å. Within this range, an exchange coupling magnetic field of 500 (Oe) or more can be obtained. More preferably, the thickness of the non-magnetic intermediate layer 59 is in the range of 5.9 to 9.4 angstroms. 1 within this range
An exchange coupling magnetic field of 000 (Oe) or more can be obtained. Within the above numerical ranges, the thickness ratio of the first fixed magnetic layer 52 to the second fixed magnetic layer 54, the thickness of the nonmagnetic intermediate layer 53 and the antiferromagnetic layer 51, and the first free magnetic layer Layer 5
By adjusting the thickness ratio of the nonmagnetic intermediate layer 59 to the thickness of the second free magnetic layer 60 and the thickness of the non-magnetic intermediate layer 59, the same ΔΔ as that of the related art can be obtained.
It is possible to obtain MR (rate of change in resistance).

Next, the method of heat treatment will be described. In the spin-valve thin-film element shown in FIGS. An antiferromagnetic material that generates a magnetic field is used. Therefore, it is necessary to appropriately control the direction and magnitude of the magnetic field applied during the heat treatment to adjust the magnetization directions of the first fixed magnetic layer 52 and the second fixed magnetic layer 54.

It is assumed that Ms · t _{P1 of} the first pinned magnetic layer 52
Is larger than Ms · t _{P2 of} the second fixed magnetic layer 54, the direction of the magnetization of the first fixed magnetic layer 52 is set to 100 to 1 k (Oe) or 5 k (Oe).
The magnetic field of e) may be applied. For example, if the first pinned magnetic layer 52 is to be oriented in the Y direction in the drawing, a magnetic field of 100 to 1 k (Oe) is applied in the Y direction in the drawing. The magnetization of the first pinned magnetic layer 52 having a large Ms · t _P1 is oriented in the direction of the magnetic field, that is, in the Y direction in the drawing. The magnetization of the first pinned magnetic layer 52 is fixed in the illustrated Y direction. On the other hand, the magnetization of the second pinned magnetic layer 54 is changed by the exchange coupling magnetic field (RKKY interaction) with the first pinned magnetic layer 52.
It is fixed in a direction opposite to the illustrated Y direction. Alternatively, a magnetic field of 5 k (Oe) or more is applied in the Y direction in the drawing. The exchange coupling magnetic field (RKKY interaction) between the first fixed magnetic layer 52 and the second fixed magnetic layer 54 is 1 k (Oe) to 5 k (Oe).
When the magnetic field of 5 k (Oe) or more is applied, both the magnetization of the first fixed magnetic layer 52 and the magnetization of the second fixed magnetic layer 54 are directed to the Y direction in the drawing. At this time, the magnetization of the first pinned magnetic layer 52 is
Exchange coupling magnetic field (exchange anisotropic magnetic field) generated at the interface with 1
Is fixed in the illustrated Y direction. On the other hand, 5k (Oe)
When the above magnetic field is removed, the magnetization of the second pinned magnetic layer 54 is fixed by being directed in the direction opposite to the Y direction in the figure by the exchange coupling magnetic field (RKKY interaction) with the first fixed magnetic layer 52. Is done.

When Ms · t _P1 of the first pinned magnetic layer 52 is smaller than Ms · t _{P2 of} the second pinned magnetic layer 54, the magnetization of the first pinned magnetic layer 52 is desired to be directed. A magnetic field of 100 to 1 k (Oe) in a direction opposite to the direction, or 5 k (Oe) or more in a direction in which the magnetization of the first pinned magnetic layer 52 is to be directed may be applied. For example, the first pinned magnetic layer 5
If it is desired to orient 2 in the illustrated Y direction, a magnetic field of 100 to 1 k (Oe) is applied in a direction opposite to the illustrated Y direction. As a result, the magnetization of the second fixed magnetic layer 54 having a large Ms · t _P2 is oriented in the direction of the magnetic field, that is, in the direction opposite to the Y direction in the figure, and exchanges with the second fixed magnetic layer 54 by the exchange coupling magnetic field (RKK).
By the Y interaction, the magnetization of the first pinned magnetic layer 52 is directed in the Y direction in the figure. The first fixed magnetic layer 52
Is fixed in the illustrated Y direction by an exchange coupling magnetic field (exchange anisotropic magnetic field) generated at the interface with the antiferromagnetic layer 51, and the magnetization of the second fixed magnetic layer 54 is in the opposite direction to the illustrated Y direction. Fixed to Alternatively, 5k (O
e) The above magnetic field may be applied. By applying a magnetic field of 5 k (Oe) or more, the magnetizations of the first fixed magnetic layer 52 and the second fixed magnetic layer 54 are both directed in the Y direction in the drawing, and the magnetization of the first fixed magnetic layer 52 becomes Antiferromagnetic layer 5
1 is fixed in the Y direction in the figure by an exchange coupling magnetic field (exchange anisotropic magnetic field) at the interface with the first magnetic field. When the magnetic field of 5 k (Oe) or more is removed, the magnetization of the second fixed magnetic layer 54 oriented in the Y direction in the drawing is changed by the exchange coupling magnetic field (RKKY interaction) with the first fixed magnetic layer 52. It is oriented and fixed in the direction opposite to the illustrated Y direction.

In the present invention, when the illustrated X direction and the illustrated Y direction are positive directions, and the opposite direction to the illustrated X direction and the opposite direction to the illustrated Y direction are negative directions, the first free magnetic layer 5
6 of Ms · t _F1 and Ms · t _F2 of the second free magnetic layer 60
The sum, the absolute value of a so-called synthetic magnetic moment than the absolute value of the resultant magnetic moment and Ms · t _P1 of the first pinned magnetic layer 52 the sum of Ms · t _P2 of the second pinned magnetic layer 54 Is also preferable. That is, |
(Ms · t _F1 + Ms · t _F2 ) / (Ms · t _p1 + Ms · t
_P2 ) It is preferred that |> 1.

The absolute value of the combined magnetic moment of the first free magnetic layer 56 and the second free magnetic layer 60 is calculated as the absolute value of the combined magnetic moment of the first fixed magnetic layer 52 and the second fixed magnetic layer 54. By making the first value larger than the first value, the first
The magnetization of the free magnetic layer 56 and the second free magnetic layer 60 is less affected by the combined magnetic moment of the first fixed magnetic layer 52 and the second fixed magnetic layer 54,
The magnetization of the free magnetic layer 56 and the second free magnetic layer 60 can be rotated with high sensitivity to an external magnetic field, and the output can be improved.

FIG. 9 is a cross-sectional view schematically showing a spin-valve thin film element according to a fifth embodiment of the present invention.
10 is a cross-sectional view of the spin-valve thin film element shown in FIG. 9 when viewed from a surface facing a recording medium. This spin-valve thin film element is obtained by reversing the order of lamination of the spin-valve thin film elements shown in FIGS. That is, from below,
Underlayer 70, second free magnetic layer 71, nonmagnetic intermediate layer 7
2, the first free magnetic layer 73, the nonmagnetic conductive layer 76, the second
, A non-magnetic intermediate layer 78, a first fixed magnetic layer 79, an antiferromagnetic layer 80, and a protective layer 81.

The underlayer 70 and the protective layer 81 are made of, for example, T
a and the like. The antiferromagnetic layer 80 is made of Pt
It is preferable to be formed of a Mn alloy. The PtMn alloy is made of NiM which has been conventionally used as an antiferromagnetic layer.
It is superior in corrosion resistance to n alloys and FeMn alloys, and has a high blocking temperature and a large exchange coupling magnetic field. In the present invention, X-Mn is used instead of the PtMn alloy.
(Where X is one or more of Pd, Ir, Rh and Ru) alloy or Pt-
Mn-X '(where X' is Pd, Ir, Rh, Ru,
An alloy which is one or more of Au and Ag) may be used.

The first fixed magnetic layer 79 and the second fixed magnetic layer 77 are formed of a Co film, a NiFe alloy, a CoFe alloy, a CoNiFe alloy, or the like. The non-magnetic intermediate layer 78 is made of Ru, Rh, Ir, Cr, Re, Cu
It is preferable to be formed of one or more alloys among them. Further, the nonmagnetic conductive layer 76 is formed of Cu or the like.

[0184] In the spin-valve type thin film element shown in FIGS. 9 and 10, (the thickness t _P2 of the second pinned magnetic layer 77) (first film thickness t _P1 of the fixed magnetic layer 79) / is 0. 33-0.9
5, or preferably in the range of 1.05 to 4, yet the film thickness t _P2 is are both 10-70 Angstroms first thickness t _P1 and the second fixed magnetic layer 77 of the pinned magnetic layer 79 Within the range, and | the first fixed magnetic layer 79
It is preferable that the thickness t _{P1 of} the second pinned magnetic layer 77 is equal to or greater than the thickness t _P2 | ≧ 2 angstroms of the second fixed magnetic layer 77. If properly adjusted within the above range, an exchange coupling magnetic field of 500 (Oe) or more can be obtained.

Further, according to the present invention, the first fixed magnetic layer 7
9 (thickness t _P1 ) / (thickness t _{P2 of} second pinned magnetic layer 77)
Is more preferably in the range of 0.53 to 0.95, or 1.05 to 1.8. In addition, the thickness t _{P1 of} the first pinned magnetic layer 79 and the thickness of the second pinned magnetic layer 77 are Film thickness t
_P2 is both within the range of 10 to 50 angstroms,
And the thickness t _P1 of │ first pinned magnetic layer 79 - and more preferably a second thickness t _P2 │ ≧ 2 angstroms or more fixed magnetic layer 77. If properly adjusted within the above range, an exchange coupling magnetic field of 1000 (Oe) or more can be obtained.

As described above, the first pinned magnetic layer 79
Magnetic film thickness Ms · t_P1Of the second pinned magnetic layer 77
Film thickness Ms ・ t_P2If there is no difference in the
And the first pinned magnetic layer 79
Thermal film thickness Ms ・ t_P1And magnetic film of second pinned magnetic layer 77
Thickness Ms ・ t_P2The exchange coupling field
Is undesirably caused. Therefore, in the present invention,
1. The thickness t of the fixed magnetic layer 79_p1And the second pinned magnetic layer 77
Film thickness t_p1(The first fixed magnetism
Magnetic film thickness Ms · t of layer 79_P1) / (Second pinned magnetic layer)
The magnetic film thickness Ms · t of 77_P2) Is from 0.33 to 0.9
5, or preferably in the range of 1.05 to 4
No. Further, in the present invention, the magnetic film of the first pinned magnetic layer 79 is provided.
Thickness Ms ・ t _P1And the magnetic film thickness M of the second pinned magnetic layer 77
st_P2Of 10-70 (Angstroms Tesla)
Within the range, and the magnetic film thickness Ms of the first pinned magnetic layer 79
・ T _P1From the magnetic film thickness Ms · t of the second pinned magnetic layer 77
_P2Absolute value minus 2 (Angstroms / Tesla) or less
It is preferably above.

(Magnetic film thickness Ms · t _{P1 of} first fixed magnetic layer 79) / (magnetic film thickness M of second fixed magnetic layer 77)
s · t _P2 ) is 0.53 to 0.95, or 1.05
More preferably, it is within the range of 1.8 to 1.8. The magnetic thickness M of the first fixed magnetic layer 79 is within the above range.
s · t _P1 and the magnetic thickness Ms · t of the second pinned magnetic layer 77
_P2 is in the range of 10 to 50 (angstrom tesla), and the magnetic film thickness Ms · t _{P1 of} the first fixed magnetic layer 79 to the magnetic film thickness Ms of the second fixed magnetic layer 77
It is preferable that the absolute value obtained by subtracting t _P2 is not less than 2 (angstrom tesla).

The thickness of the nonmagnetic intermediate layer 78 interposed between the first fixed magnetic layer 79 and the second fixed magnetic layer 77 is
Preferably, it is in the range of 2.5 to 6.4, or 6.6 to 10.7 angstroms. Within this range, an exchange coupling magnetic field of 500 (Oe) or more can be obtained. More preferably, it is in the range of 2.8 to 6.2 angstroms or 6.8 to 10.3 angstroms, and within this range, an exchange coupling magnetic field of 1000 (Oe) or more can be obtained. .

It is preferable that the thickness of the antiferromagnetic layer 80 is 90 Å or more. Within this range, an exchange coupling magnetic field of 500 (Oe) or more can be obtained. More preferably, it is 100 Å or more, and within this range, an exchange coupling magnetic field of 1000 (Oe) or more can be obtained.

In the spin-valve type thin film element shown in FIG. 10, the free magnetic layer is formed by being divided into two layers.
A first free magnetic layer 73 is provided on the side in contact with the nonmagnetic conductive layer 76.
Is formed, and the other free magnetic layer is a second free magnetic layer 71. As shown in FIG. 10, the first free magnetic layer 73 is formed of two layers, and the layer 75 formed on the side in contact with the nonmagnetic conductive layer 76 is formed of a Co film. The layer 74 formed on the side in contact with the nonmagnetic intermediate layer 72 and the second free magnetic layer 71 are made of, for example, Ni
It is formed of an Fe alloy, a CoFe alloy, a CoNiFe alloy, or the like.

The side surface of the spin valve film from the underlayer 70 to the protective layer 81 shown in FIG. 10 is cut into an inclined surface, and the spin valve film is formed in a trapezoidal shape. Hard bias layers 82 and 82 and conductive layers 83 and 83 are formed on both sides of the spin valve film. The hard bias layer 82 is formed of a Co—Pt alloy or a Co—Cr—Pt alloy, and the conductive layer 83 is formed of Cu, Cr, or the like.

A non-magnetic intermediate layer 72 is interposed between the first free magnetic layer 73 and the second free magnetic layer 71 shown in FIG. 10, and the first free magnetic layer 73 and the second free magnetic layer The magnetization of the first free magnetic layer 73 and the magnetization of the second free magnetic layer 71 are in an anti-parallel state (ferri state) due to an exchange coupling magnetic field (RKKY interaction) generated between the layers 71. In the spin-valve type thin film element shown in FIG.
For example, the thickness T _F1 of the first free magnetic layer 73 is formed to be larger than the thickness T _{F2 of} the second free magnetic layer 71.
Ms · t _F1 of the first free magnetic layer 73 is set to be larger than Ms · t _{F2 of} the second free magnetic layer 71,
When a bias magnetic field is applied in the direction, the magnetization of the first free magnetic layer 73 having a large Ms · t _F1 is influenced by the bias magnetic field, and is aligned in the X direction in the drawing. , The magnetization of the second free magnetic layer 71 having a small Ms · t _F2 is aligned in the direction opposite to the X direction in the drawing. In the present invention, the film thickness t _{F1 of} the first free magnetic layer 73 is formed smaller than the film thickness t _{F2 of} the second free magnetic layer 71, and Ms · t _{F1 of} the first free magnetic layer 73. May be set smaller than Ms · t _{F2 of} the second free magnetic layer 71.

When an external magnetic field enters from the Y direction in the figure, the magnetizations of the first free magnetic layer 73 and the second free magnetic layer 71 rotate under the influence of the external magnetic field while maintaining a ferrimagnetic state. I do. The magnetization direction of the first free magnetic layer 73 contributing to ΔMR and the second pinned magnetic layer 71
The electrical resistance changes depending on the relationship with the fixed magnetization of the semiconductor device, and a signal of an external magnetic field is detected. In the present invention, the thickness T _F1 of the first free magnetic layer 73 and the thickness T _{F2 of} the second free magnetic layer 71 are different.
The film thickness ratio can be optimized, and a larger exchange coupling magnetic field can be obtained, and at the same time, it is possible to obtain a ΔMR that is almost the same as that of the related art.

In the present invention, (the thickness t _{F1 of} the first free magnetic layer 73 / the thickness t _{F2 of} the second free magnetic layer 71) is calculated as follows.
It is preferably in the range of 0.56 to 0.83, or 1.25 to 5. Within this range, an exchange coupling magnetic field of at least 500 (Oe) or more can be obtained. Further, in the present invention, the (first free magnetic layer 73
The thickness t _F1 / thickness t _F2 of the second free magnetic layer 71),
More preferably, it is in the range of 0.61 to 0.83, or 1.25 to 2.1. Within this range, an exchange coupling magnetic field of at least 1000 (Oe) can be obtained.

The magnetic film thickness Ms · t _{F1 of} the first free magnetic layer 73 and the magnetic film thickness M of the second free magnetic layer 71
If there is no difference in s · t _F2 , the magnetization state is unlikely to be in the ferri state, and the magnetic film thickness Ms · t _{F1 of} the first free magnetic layer 73 and the magnetic film of the second free magnetic layer 71 If the difference between the thicknesses Ms · t _F2 is too large, the exchange coupling magnetic field is undesirably reduced. Therefore, in the present invention, the first
The thickness t _F1 of the free magnetic layer 73 and the second free magnetic layer 7
In the same manner as the film thickness ratio to the film thickness t _{F2 of} (1), (the magnetic film thickness Ms · t _{F1 of} the first free magnetic layer 73) / (the magnetic film thickness Ms · of the second free magnetic layer 71) t _F2 ) is from 0.56 to
Preferably, it is 0.83 or in the range of 1.25 to 5. In the present invention, the first free magnetic layer 73
Magnetic film thickness Ms · t _F1 ) / (second free magnetic layer 71)
It is more preferable magnetic film thickness Ms · t _F2) of 0.61 to 0.83, or in the range of 1.25 to 2.1.

In the present invention, the first free magnetic layer 73
The nonmagnetic intermediate layer 72 interposed between the second free magnetic layer 71 and the second free magnetic layer 71 is preferably formed of one or more alloys of Ru, Rh, Ir, Cr, Re, and Cu. . Further, the thickness of the nonmagnetic intermediate layer 72 is 5.5.
Preferably, it is in the range of １10.0 Å. Within this range, an exchange coupling magnetic field of 500 (Oe) or more can be obtained. More preferably, the thickness of the non-magnetic intermediate layer 72 is in the range of 5.9 to 9.4 angstroms. 1 within this range
An exchange coupling magnetic field of 000 (Oe) or more can be obtained. The first fixed magnetic layer 79 and the second fixed magnetic layer 77
, The film thickness of the nonmagnetic intermediate layer 78 and the antiferromagnetic layer 80, the film thickness ratio of the first free magnetic layer 73 to the second free magnetic layer 71, and the nonmagnetic intermediate layer 72. By properly adjusting the film thickness within the above-described range, it is possible to obtain a ΔMR (rate of change in resistance) comparable to that of the related art.

Next, the method of heat treatment will be described. Provisional
The Ms · t of the first pinned magnetic layer 79 is _P1Is the second
Ms · t of the pinned magnetic layer 77_P2If greater than
The direction of the magnetization of the first pinned magnetic layer 79 is
Apply a magnetic field of 0 to 1k (Oe) or 5k (Oe)
Just do it. Alternatively, Ms · t of the first pinned magnetic layer 79
_P1Is the Ms · t of the second pinned magnetic layer 77._P2Less than
In this case, it is desired to direct the magnetization of the first pinned magnetic layer 79.
100-1k (Oe) in the direction opposite to the direction, or
5k (O) in the direction in which the magnetization of the
e) The above magnetic field may be applied. In the present invention,
The magnetization of the first fixed magnetic layer 79 is fixed in the Y direction in the figure.
The magnetization of the second pinned magnetic layer 77 is
It is fixed in the opposite direction. Or the first fixed magnet
The magnetization of the active layer 79 is fixed in a direction opposite to the Y direction in the drawing,
The magnetization of the second fixed magnetic layer 77 is fixed in the Y direction in the figure.
Have been.

In the present invention, when the illustrated X direction and the illustrated Y direction are defined as the positive direction, and the opposite direction to the illustrated X direction and the opposite direction to the illustrated Y direction are defined as the negative direction, the first free magnetic layer 7
3 Ms · t _F1 and Ms · t _F2 of the second free magnetic layer 71
The sum, the absolute value of a so-called synthetic magnetic moment than the absolute value of the resultant magnetic moment and Ms · t _P1 of the first pinned magnetic layer 79 the sum of Ms · t _P2 of the second pinned magnetic layer 77 It is also preferable that the value is larger. That is, |
(Ms · t _F1 + Ms · t _F2 ) / (Ms · t _p1 + Ms · t
_P2 ) It is preferred that |> 1.

The absolute value of the combined magnetic moment of the first free magnetic layer 73 and the second free magnetic layer 71 is calculated as the absolute value of the combined magnetic moment of the first fixed magnetic layer 79 and the second fixed magnetic layer 77. By setting the value larger than the first value,
The magnetizations of the free magnetic layer 79 and the second free magnetic layer 77 are less affected by the combined magnetic moment of the first fixed magnetic layer 79 and the second fixed magnetic layer 77, and
The magnetization of the free magnetic layer 73 and the second free magnetic layer 71 rotates with good sensitivity to an external magnetic field, and the output can be improved.

FIG. 11 is a cross-sectional view showing the structure of a spin-valve thin film element according to a sixth embodiment of the present invention.
FIG. 12 is a cross-sectional view of the spin-valve thin-film element shown in FIG. 11 as viewed from a surface facing a recording medium. This spin-valve thin-film element is a dual spin-valve thin-film element in which a nonmagnetic conductive layer, a fixed magnetic layer, and an antiferromagnetic layer are stacked above and below a free magnetic layer, and the free magnetic layer, And the pinned magnetic layer is divided into two layers via a non-magnetic intermediate layer.

The lowermost layer shown in FIGS. 11 and 12 is an underlayer 91, on which an antiferromagnetic layer 92, a first pinned magnetic layer (lower) 93, Nonmagnetic intermediate layer 94 (lower), second pinned magnetic layer (lower) 95, nonmagnetic conductive layer 96, second free magnetic layer 97, nonmagnetic intermediate layer 1
00, first free magnetic layer 101, nonmagnetic conductive layer 10
4, a second fixed magnetic layer (upper) 105, a nonmagnetic intermediate layer (upper) 106, a first fixed magnetic layer (upper) 107, an antiferromagnetic layer 108, and a protective layer 109.

First, the material will be described. Antiferromagnetic layer 9
Preferably, 2108 is formed of a PtMn alloy. The PtMn alloy has excellent corrosion resistance, a high blocking temperature, and a large exchange coupling magnetic field (exchange anisotropic magnetic field) as compared with a NiMn alloy or a FeMn alloy conventionally used as an antiferromagnetic layer. In the present invention,
X—Mn (where X is P
an alloy of d, Ir, Rh, or Ru; or an alloy of Pt—Mn—X ′ (where X ′ is any one of Pd, Ir, Rh, Ru, Au, and Ag) Or one or more elements) may be used.

First fixed magnetic layer (lower) 93, (upper) 10
7, and the second pinned magnetic layer (lower) 95, (upper) 105
Represents a Co film, a NiFe alloy, a CoFe alloy, or C
oNiFe alloy or the like. Non-magnetic intermediate layers (lower) 94 and (upper) formed between the first fixed magnetic layers (lower) 93 and (upper) 107 and the second fixed magnetic layers (lower) 95 and (upper) 105. 106 and the non-magnetic intermediate layer 100 formed between the first free magnetic layer 101 and the second free magnetic layer 97 include Ru, Rh, Ir, Cr, Re,
It is preferable to be formed of one or more alloys of Cu. Further, the nonmagnetic conductive layers 96 and 104 are formed of Cu or the like.

As shown in FIG. 11, the first free magnetic layer 101 and the second free magnetic layer 97 are formed of two layers. The layer 103 of the first free magnetic layer 101 and the layer 98 of the second free magnetic layer 97 formed on the side in contact with the nonmagnetic conductive layers 96 and 104 are formed of a Co film. Further, the layer 102 of the first free magnetic layer 101 and the layer 99 of the second free magnetic layer 97 formed via the nonmagnetic intermediate layer 100 are made of, for example, a NiFe alloy, a CoFe alloy, or a CoNiFe alloy. Is formed.
By forming the layers 98 and 103 in contact with the non-magnetic conductive layers 96 and 104 with a Co film, ΔMR can be increased and diffusion with the non-magnetic conductive layers 96 and 104 can be prevented.

Next, the appropriate range of the thickness of each layer will be described. First the first pinned magnetic layer formed on the lower side of the free magnetic layer and the thickness t _P1 (bottom) 93, the thickness ratio between the film thickness t _P2 of the second pinned magnetic layer (lower) 95, and the film thickness ratio between the film thickness t _P2 of the free magnetic layer first pinned magnetic layer formed on the upper side of (above) 107 thickness t _P1 and the second fixed magnetic layer (upper) 105 ( First pinned magnetic layer (bottom) 93, (top) 1
07 film thickness t _P1 ) / (second fixed magnetic layer (lower) 95,
The thickness t _P2 of (upper) 105 is preferably in the range of 0.33 to 0.95 or 1.05 to 4, and the first fixed magnetic layer (lower) 93, (upper) ) 107 and the second pinned magnetic layers (lower) 95 and (upper) 105
Both are formed within the range of 10 to 70 angstroms,
And | thickness t _{P1 of} first fixed magnetic layer (lower) 93 and (upper) 107 -second fixed magnetic layer (lower) 95 and (upper) 105
It is preferable that the film is formed with a thickness t _P2 | ≧ 2 angstroms. Within the above range, an exchange coupling magnetic field of 500 (Oe) or more can be obtained.

In the present invention, the film thickness t _{P1 of} (first fixed magnetic layer (lower) 93 and (upper) 107) / (film thickness of second fixed magnetic layer (lower) 95 and (upper) 105) t _P2 ) is 0.
It is preferably in the range of 53 to 0.95, or 1.05 to 1.8, and the first fixed magnetic layer (lower)
93, (top) 107 and the second pinned magnetic layer (bottom) 95,
The film thickness of the (upper) 105 is formed within the range of 10 to 50 angstroms, and | the film thickness t _{P1 of} the first pinned magnetic layers (lower) 93 and (upper) 107 -the second pinned magnetic layer. It is preferable that the layers (lower) 95 and (upper) 105 be formed with a thickness t _P2 | ≧ 2 Å. Within the above range, an exchange coupling magnetic field of 1000 (Oe) or more can be obtained.

In the present invention, as described above, the anti-ferromagnetic layers 92 and 108 are made of PtMn alloy or the like at the interfaces with the first fixed magnetic layers (lower) 93 and (upper) 107 at the exchange coupling magnetic field (exchange magnetic field). An antiferromagnetic material that requires heat treatment to generate an isotropic magnetic field is used. However, at the interface between the antiferromagnetic layer 92 formed below the free magnetic layer and the first pinned magnetic layer (lower) 93, diffusion of the metal element easily occurs, and the thermal diffusion layer is easily formed. Therefore, the magnetic film thickness functioning as the first fixed magnetic layer (lower) 93 is smaller than the actual film thickness t _P1 . Accordingly, in order to make the exchange coupling magnetic field generated in the laminated film above the free magnetic layer substantially equal to the exchange coupling magnetic field generated in the laminated film below the free magnetic layer, the exchange coupling magnetic field is formed below the free magnetic layer. The thickness t _{P1 of the} first fixed magnetic layer (lower) 93
/ Thickness t _{P2 of} second pinned magnetic layer (lower) 95 is formed above free magnetic layer (thickness t _{P1 of} first fixed magnetic layer (upper) 107 / second thickness). Fixed magnetic layer (upper) 10
It is preferable that the thickness is larger than the thickness t _P2 of No. 5. By making the exchange coupling magnetic field generated from the laminated film above the free magnetic layer equal to the exchange coupling magnetic field generated from the laminated film below the free magnetic layer, the manufacturing process of the exchange coupling magnetic field is less deteriorated, and the reliability of the magnetic head is reduced. Performance can be improved.

As described above, the first pinned magnetic layer (lower)
93, (top) 107 magnetic film thickness Ms · t _P1 and the second pinned magnetic layer (lower) 95, Ms · magnetic thickness of the (top) 105
If there is no difference in t _P2 to some extent, the magnetization state is unlikely to be in the ferri state, and the first pinned magnetic layers (bottom) 93 and (top)
107 magnetic film thickness Ms · t _P1 and the second pinned magnetic layer (lower) 95, even if the difference between the magnetic film thickness Ms · t _P2 (upper) 105 is too large, a decrease in the exchange coupling magnetic field Connection is not good. Therefore, in the present invention, the first pinned magnetic layer (lower) 93, (top) 107 thickness t _P1 and the second fixed magnetic layer (lower) 95, the thickness ratio of the thickness t _P2 (upper) 105 In the same manner as (1), (first fixed magnetic layer (lower) 93, (upper) 107
Magnetic film thickness Ms · t _P1 ) / (second fixed magnetic layer (lower)
95, (upper) 105, the magnetic film thickness Ms · t _P2 ) is 0.
It is preferably in the range of 33 to 0.95, or 1.05 to 4. In the present invention, the magnetic film thickness Ms · t _{P1 of} the first fixed magnetic layers (lower) 93 and (upper) 107 and the magnetic film thickness of the second fixed magnetic layers (lower) 95 and (upper) 105 Ms · t _P2 is in the range of 10 to 70 (Angstroms / Tesla) and the first fixed magnetic layer (lower)
(Top) 107 second pinned magnetic layer from the magnetic film thickness Ms · t _P1 (bottom) 95, the magnetic film thickness Ms · t _P2 (upper) 105
Is preferably equal to or greater than 2 (Angstroms / Tesla).

The first fixed magnetic layer (lower) 93,
(Top) Magnetic film thickness Ms · t _{P1 of} 107 / (Second pinned magnetic layer (bottom) 95, Magnetic film thickness of (top) 105 Ms · t
_P2 ) is 0.53-0.95, or 1.05-1.
More preferably, it is within the range of 8. Also, within the above range, the first pinned magnetic layers (lower) 93 and (upper) 107
Magnetic film thickness Ms · t _P1 and second fixed magnetic layer (lower) 9
The magnetic film thickness Ms · t _P2 of 105, (top) 105 is 10 to 10
50 (angstrom tesla), and from the magnetic film thickness Ms · t _{P1 of} the first fixed magnetic layer (lower) 93 and (upper) 107, the second fixed magnetic layer (lower) 95,
(Above) The absolute value obtained by subtracting the magnetic film thickness Ms · t _P2 of 105 is preferably 2 (angstrom · tesla) or more.

According to the present invention, the non-magnetic intermediate layer interposed between the first fixed magnetic layer (lower) 93 and the second fixed magnetic layer (lower) 95 formed below the free magnetic layer. The lower layer 94 preferably has a thickness in the range of 3.6 to 9.6 angstroms. 5 within this range
An exchange coupling magnetic field of 00 (Oe) or more can be obtained.
More preferably, it is within the range of 4 to 9.4 angstroms, and within this range, an exchange coupling magnetic field of 1000 (Oe) or more can be obtained.

The non-magnetic intermediate layer (upper) 10 interposed between the first fixed magnetic layer (upper) 107 and the second fixed magnetic layer (upper) 105 formed above the free magnetic layer.
The film thickness of 6 is preferably in the range of 2.5 to 6.4 angstroms, or 6.6 to 10.7 angstroms. Within this range, at least 500
It is possible to obtain an exchange coupling magnetic field of (Oe) or more.
Also, 2.8 to 6.2 angstroms, or 6.
It is more preferably in the range of 8 to 10.3 angstroms, and within this range, an exchange coupling magnetic field of 1000 (Oe) or more can be obtained.

Further, in the present invention, the antiferromagnetic layers 92, 10
8 preferably has a thickness of 100 Å or more. By forming the antiferromagnetic layers 92 and 108 at a thickness of 100 Å or more, at least 50 Å is formed.
An exchange coupling magnetic field of 0 (Oe) or more can be obtained. In the present invention, the thickness of the antiferromagnetic layers 92 and 108 is set to 1
If formed at 10 Å or more, at least 1
An exchange coupling magnetic field of 000 (Oe) or more can be obtained.

According to the present invention, the first free magnetic layer 10
In the case where the thickness of the first free magnetic layer 101 is t _F1 and the thickness of the second free magnetic layer 97 is t _F2 ,
_F1 / (film thickness t _{F2 of} the second free magnetic layer 97) is 0.56
０．８0.83, or 1.25-5. Within this range, an exchange coupling magnetic field of 500 (Oe) or more can be obtained. In addition, the above (thickness of first free magnetic layer / thickness of second free magnetic layer)
Is more preferably in the range of 0.61 to 0.83, or 1.25 to 2.1, and within this range, an exchange coupling magnetic field of 1000 (Oe) or more can be obtained.

[0214] Also, the first free somewhat difference in magnetic film thickness Ms · t _F2 of magnetic film thickness Ms · t _F1 and the second free magnetic layer 97 of the magnetic layer 101 is not present, the magnetization state ferrimagnetic state And even if the difference between the magnetic film thickness Ms · t _{F1 of} the first free magnetic layer 101 and the magnetic film thickness Ms · t _F2 of the second free magnetic layer 97 becomes too large, the exchange coupling may occur. This is undesirable because it leads to a decrease in the magnetic field. Therefore, in the present invention,
In the same manner as the film thickness ratio of the film thickness t _{F1 of} the first free magnetic layer 101 to the film thickness t _{F2 of} the second free magnetic layer 97, (the magnetic film thickness Ms · t _F1 ) / (second
The magnetic film thickness Ms · t _F2 ) of the free magnetic layer 97 of FIG.
It is preferably in the range of 56 to 0.83, or 1.25 to 5. In the present invention, (the magnetic film thickness Ms · t _{F1 of} the first free magnetic layer 101) / (the magnetic film thickness Ms · t _{F2 of} the second free magnetic layer 97) is 0.61 to 0.8.
3, or more preferably in the range of 1.25 to 2.1.

The non-magnetic intermediate layer 100 interposed between the first free magnetic layer 101 and the second free magnetic layer 97
Is preferably formed within a range of 5.5 to 10.0 angstroms, and within this range, an exchange coupling magnetic field of 500 (Oe) or more can be obtained. . The thickness of the non-magnetic intermediate layer 100 is more preferably in the range of 5.9 to 9.4 angstroms, and within this range, 1000 (O
e) The above exchange coupling magnetic field can be obtained.

In the present invention, the first pinned magnetic layer (lower)
93, (top) 107 and the second pinned magnetic layer (bottom) 95,
(Upper) Film thickness ratio with 105, first fixed magnetic layer (lower) 9
3, (top) 107 and the second pinned magnetic layer (bottom) 95,
(Upper) 105, non-magnetic intermediate layer (lower) 94, (upper) 10
6, and the thicknesses of the antiferromagnetic layers 92 and 108, the thickness ratio of the first free magnetic layer 101 to the second free magnetic layer 97, and the thickness of the nonmagnetic intermediate layer 100 are within the above ranges. If it is adjusted appropriately, it is possible to obtain a ΔMR comparable to that of the related art.

By the way, in the dual spin-valve thin film element shown in FIGS. 11 and 12, the second fixed magnetic layers (lower) 95 and (upper) formed above and below the free magnetic layer.
The magnetizations of 105 must be oriented in opposite directions. This is formed by dividing the free magnetic layer into two layers, a first free magnetic layer 101 and a second free magnetic layer 97. The magnetization of the first free magnetic layer 101 and the second free magnetic layer This is because the magnetization 97 is antiparallel.

For example, as shown in FIGS. 11 and 12, if the magnetization of the first free magnetic layer 101 is magnetized in the direction opposite to the X direction in the figure, the first free magnetic layer 101
The exchange coupling magnetic field (RKKY interaction) with
Of the free magnetic layer 97 is magnetized in the X direction in the figure. The magnetizations of the first free magnetic layer 101 and the second free magnetic layer 97 are reversed under the influence of an external magnetic field while maintaining a ferrimagnetic state.

In the dual spin-valve thin film device shown in FIGS. 11 and 12, the magnetization of the first free magnetic layer 101 and the magnetization of the second free magnetic layer 97 are both layers involved in ΔMR. The first free magnetic layer 10
The electric resistance changes depending on the relationship between the variable magnetization of the first and second free magnetic layers 97 and the fixed magnetization of the second fixed magnetic layers (lower) 95 and (upper) 105. In order to exhibit a function as a dual spin-valve thin film element capable of expecting a large ΔMR as compared with a single spin-valve thin film element, it is necessary to change the resistance between the first free magnetic layer 101 and the second pinned magnetic layer (upper) 105. The second pinned magnetic layers (lower) 95 and (upper) 10 are so arranged that the resistance changes of the second free magnetic layer 97 and the second pinned magnetic layer (lower) 95 show the same fluctuation.
5 needs to be controlled. That is, the first
Free magnetic layer 101 and second pinned magnetic layer (upper) 105
When the change in resistance with respect to the maximum becomes maximum, the second free magnetic layer 9
7 and the second pinned magnetic layer (lower) 95 also have a maximum resistance change, and the first free magnetic layer 101 and the second fixed magnetic layer (upper) 105 have a minimum resistance change. The resistance change between the second free magnetic layer 97 and the second pinned magnetic layer (lower) 95 should be minimized.

Therefore, in the dual spin-valve thin film element shown in FIGS. 11 and 12, since the magnetizations of the first free magnetic layer 101 and the second free magnetic layer 97 are antiparallel, the second fixed magnetic layer It is necessary to magnetize the magnetization of the layer (upper) 105 and the magnetization of the second pinned magnetic layer (lower) 95 in opposite directions.

In the present invention, for the reasons described above, the second
The magnetization of the fixed magnetic layer (lower) 95 is fixed in the opposite direction to the magnetization of the second fixed magnetic layer (upper) 105. In order to control such a magnetization direction, It is necessary to appropriately adjust Ms · t of each fixed magnetic layer and the direction and magnitude of the magnetic field applied during the heat treatment. First, with respect to Ms · t of each fixed magnetic layer, Ms · t _{P1 of} the first fixed magnetic layer (upper) 107 formed above the free magnetic layer.
Is larger than Ms · t _{P2 of} the second pinned magnetic layer (upper) 105 and Ms · t of the first pinned magnetic layer (lower) 93 formed below the free magnetic layer. _P1 is the second
Fixed or smaller than Ms · t _P2 of the magnetic layer (lower) 95, or the first pinned magnetic layer formed above the free magnetic layer Ms · t _P1 (top) 107, a 2
Ms · t _P1 of the first fixed magnetic layer (lower) 93 formed below the free magnetic layer and smaller than Ms · t _P2 of the fixed magnetic layer 105 (upper) It is necessary to be larger than Ms · t _{P2 of the} second fixed magnetic layer (lower) 95.

In the present invention, the first pinned magnetic layers (lower) 93 and (upper) 107 are subjected to annealing (heat treatment) in a magnetic field such as a PtMn alloy as the antiferromagnetic layers 92 and 108.
Since an antiferromagnetic material that generates an exchange coupling magnetic field at the interface with the substrate is used, the direction and magnitude of the magnetic field applied during the heat treatment must be properly adjusted. In the present invention, Ms · t _P1 of the first fixed magnetic layer (upper) 107 formed above the free magnetic layer is larger than Ms · t _{P2 of} the second fixed magnetic layer (upper) 105. In addition, Ms · t _P1 of the first pinned magnetic layer (lower) 93 formed below the free magnetic layer is changed to the second pinned magnetic layer (lower) 9.
5 is smaller than Ms · t _{P2 of} 100 to 1 k in the direction in which the magnetization of the first fixed magnetic layer (upper) 107 formed above the free magnetic layer is to be directed.
(Oe) magnetic field is applied.

For example, as shown in FIG. 11, when the magnetization of the first pinned magnetic layer (upper) 107 is desired to be directed in the illustrated Y direction, a magnetic field of 100 to 1 k (Oe) is applied in the illustrated Y direction. . Here, the first fixed magnetic layer (upper) 107 having a larger Ms · t _P1 and the second fixed magnetic layer (lower) 95 formed below the free magnetic layer are both in the direction of the applied magnetic field, That is, it faces the Y direction in the figure. On the other hand, the magnetization of the second pinned magnetic layer (upper) 105 having a smaller Ms · t _P2 formed above the free magnetic layer is the same as that of the first pinned magnetic layer (upper) 1.
07 with the exchange coupling magnetic field (RKKY interaction)
It is magnetized antiparallel to the magnetization direction of the first pinned magnetic layer (upper) 107. Similarly, the magnetization of the first fixed magnetic layer (lower) 93 formed below the free magnetic layer and having a smaller Ms · t _P1 becomes a ferrimagnetic state with the magnetization of the second fixed magnetic layer (lower) 95. As a result, it is magnetized in a direction opposite to the illustrated Y direction. Due to the exchange coupling magnetic field (exchange anisotropic magnetic field) generated at the interface with the antiferromagnetic layer 108 by the heat treatment, the first fixed magnetic layer (upper) 10 formed above the free magnetic layer
7 is fixed in the illustrated Y direction, and the magnetization of the second pinned magnetic layer (upper) 105 is fixed in the direction opposite to the illustrated Y direction. Similarly, the magnetization of the first fixed magnetic layer (lower) 93 formed below the free magnetic layer is fixed in the direction opposite to the Y direction in the figure by the exchange coupling magnetic field (exchange anisotropic magnetic field). , The magnetization of the second pinned magnetic layer (lower) 95 is Y
Fixed in the direction.

Further, Ms · t _P1 of the first pinned magnetic layer (upper) 107 formed above the free magnetic layer is smaller than Ms · t _{P2 of} the second pinned magnetic layer (upper) 105. and, and, the first fixed magnetic layer which is formed below the free magnetic layer Ms · t _P1 (bottom) 93, than Ms · t _P2 of the second pinned magnetic layer (lower) 95 If it is increased, the magnetic field is increased by 100 in the direction in which the magnetization of the first pinned magnetic layer (lower) 93 formed below the free magnetic layer is to be directed.
１1 k (Oe). As described above, the second fixed magnetic layers (lower) 95 formed above and below the free magnetic layer
By magnetizing (upper) 105 in the opposite direction, ΔMR comparable to that of a conventional dual spin-valve thin film element can be obtained.

In the present invention, the magnetization of the first free magnetic layer 101 and the magnetization of the second free magnetic layer 97 in the ferri-state can be reversed with higher sensitivity to an external magnetic field. The combined magnetic moment obtained by adding the magnetic moment of the first free magnetic layer 101 and the magnetic moment of the second free magnetic layer 97 is equal to the first fixed magnetic layer ( Bottom) The composite magnetic moment obtained by adding the magnetic moment of 93 and the magnetic moment of the second pinned magnetic layer (bottom) 95, and the first pinned magnetic layer formed above the free magnetic layer (top) What is necessary is just to make it larger than the combined magnetic moment obtained by adding the magnetic moment of 107 and the magnetic moment of the second pinned magnetic layer (upper) 105. That is, for example, when the magnetic moment in the illustrated X direction and the illustrated Y direction is a positive value, and the magnetic moment in the opposite direction to the illustrated X direction and the opposite direction to the illustrated Y direction is a negative value, the resultant magnetic moment | Ms · t _{F 1} + Ms · t _F2 │ are the first fixed magnetic layer (upper) 107 and the second fixed magnetic layer (upper) 105
Magnetic moment |
_{Ms · t P1 + Ms · t} P2 │ and the first pinned magnetic layer (lower) greater than the resultant magnetic moment _{│Ms · t P1 + Ms · t} P2 │ between 93 and the second pinned magnetic layer (lower) 95 Preferably.

As described above, in the spin-valve type thin film element shown in FIGS. 7 to 12, not only the fixed magnetic layer but also the free magnetic layer are connected to the first free magnetic layer and the second free magnetic layer via the nonmagnetic intermediate layer. The two free magnetic layers are divided into two layers, and the exchange coupling magnetic field (RKKY interaction) generated between the two free magnetic layers changes the magnetization of the two free magnetic layers into an antiparallel state (a ferri state). The magnetization of the first free magnetic layer and the magnetization of the second free magnetic layer can be reversed with high sensitivity to an external magnetic field.

Further, in the present invention, the thickness ratio between the first free magnetic layer and the second free magnetic layer, and the non-magnetic layer interposed between the first free magnetic layer and the second free magnetic layer. The thickness of the intermediate layer, the ratio of the thickness of the first fixed magnetic layer to the thickness of the second fixed magnetic layer, and the thickness of the non-magnetic intermediate layer interposed between the first fixed magnetic layer and the second fixed magnetic layer. By forming the thickness of the layer and the thickness of the antiferromagnetic layer within an appropriate range,
The exchange coupling magnetic field can be increased, and the magnetization states of the first fixed magnetic layer and the second fixed magnetic layer are set as fixed magnetization,
The magnetization state of the first free magnetic layer and the second free magnetic layer can be maintained as a thermally stable ferri-state by changing the magnetization state, and a ΔMR equivalent to that of the related art can be obtained. It has become. In the present invention, by further adjusting the direction of the sense current, the antiparallel state (ferri state) between the magnetization of the first fixed magnetic layer and the magnetization of the second fixed magnetic layer.
Can be kept more thermally stable.

In the spin-valve type thin film element, conductive layers are formed on both sides of a laminated film composed of an antiferromagnetic layer, a pinned magnetic layer, a nonmagnetic conductive layer, and a free magnetic layer. Swept away. The sense current mainly flows to the nonmagnetic conductive layer having a small specific resistance, the interface between the nonmagnetic conductive layer and the fixed magnetic layer, and the interface between the nonmagnetic conductive layer and the free magnetic layer. In the present invention, the fixed magnetic layer is divided into a first fixed magnetic layer and a second fixed magnetic layer, and the sense current is mainly applied to an interface between the second fixed magnetic layer and the nonmagnetic conductive layer. Flowing. When the sense current is applied,
A sense current magnetic field is formed by the right-hand rule.
In the present invention, the sense current magnetic field is set in the same direction as the direction of the synthetic magnetic moment that can be obtained by adding the magnetic moment of the first fixed magnetic layer and the magnetic moment of the second fixed magnetic layer. The direction of current flow is adjusted.

In the spin valve type thin film element shown in FIG.
A second fixed magnetic layer 54 is formed below the nonmagnetic conductive layer 15. In this case, the first pinned magnetic layer 5
The direction of the sense current magnetic field is adjusted to the magnetization direction of the fixed magnetic layer having the larger magnetic moment of the second and second fixed magnetic layers 54. As shown in FIG. 1, the magnetic moment of the second pinned magnetic layer 54 is larger than the magnetic moment of the first pinned magnetic layer 52,
The magnetic moment No. 4 is directed in a direction opposite to the illustrated Y direction (left direction in the drawing). Therefore, the first pinned magnetic layer 52
Is combined with the magnetic moment of the second pinned magnetic layer 54, the combined magnetic moment is directed in the opposite direction (left direction in the figure) to the Y direction in the figure.

As described above, the nonmagnetic conductive layer 15 is formed above the second fixed magnetic layer 54 and the first fixed magnetic layer 52. For this reason, the sense current magnetic field mainly generated by the sense current 112 flowing around the nonmagnetic conductive layer 15 is such that the sense current The flow direction of 112 may be controlled. By doing so, the direction of the combined magnetic moment of the first pinned magnetic layer 52 and the second pinned magnetic layer 54 coincides with the direction of the sense current magnetic field.

As shown in FIG. 1, the sense current 112 flows in the X direction in the figure. According to the right-hand rule, a sense current magnetic field formed by flowing a sense current is formed clockwise with respect to the plane of the drawing. Therefore, a sense current magnetic field in the left direction in the drawing (the direction opposite to the Y direction in the drawing) is applied to the layer below the nonmagnetic conductive layer 15, and the combined magnetic moment is reinforced by the sense current magnetic field. The exchange coupling magnetic field (RKKY interaction) acting between the first fixed magnetic layer 52 and the second fixed magnetic layer 54 is amplified, and the magnetization of the first fixed magnetic layer 52 and the second It is possible to more thermally stabilize the antiparallel state of magnetization of the fixed magnetic layer 54.

In particular, when a sense current of 1 mA flows, about 30
It has been found that a sense current magnetic field of about (Oe) is generated and the element temperature rises by about 15 ° C. Further, the rotation speed of the recording medium increases to about 1000 rpm, and the temperature in the apparatus increases to about 100 ° C. due to the increase in the rotation speed. Therefore, for example, when a sense current of 10 mA flows, the element temperature of the spin-valve thin film element is about 250 ° C.
And the sense current magnetic field is also 300 (O
e).

In the case where such a large sense current flows under an extremely high environmental temperature, the magnetic moment of the first fixed magnetic layer 52 and the second fixed magnetic layer 5
4 is opposite to the direction of the sensed magnetic field, which can be obtained by adding the fixed magnetic layer 52 to the first fixed magnetic layer 52 and the second fixed magnetic layer 5.
The antiparallel state with the magnetization of No. 4 is easily broken.

In order to be able to withstand a high environmental temperature, in addition to adjusting the direction of the sense current magnetic field, an anti-ferromagnetic material having a high blocking temperature is used.
Therefore, in the present invention, a PtMn alloy having a blocking temperature of about 400 ° C. is used.

The combined magnetic moment formed by the magnetic moment of the first fixed magnetic layer 52 and the magnetic moment of the second fixed magnetic layer 54 shown in FIG. 1 is directed rightward in the figure (Y direction in the figure). In this case, the sense current may be caused to flow in the direction opposite to the X direction in the drawing, so that the sense current magnetic field is formed counterclockwise with respect to the page.

Next, the sense current direction of the spin valve type thin film element shown in FIG. 3 will be described. In FIG. 3, a second fixed magnetic layer 25 and a first fixed magnetic layer 27 are formed above the nonmagnetic conductive layer 24. As shown in FIG.
The magnetic moment of the fixed magnetic layer 27 is larger than the magnetic moment of the second fixed magnetic layer 25, and the direction of the magnetic moment of the first fixed magnetic layer 27 is in the Y direction (right direction in the drawing). ). Therefore, the combined magnetic moment obtained by adding the magnetic moment of the first fixed magnetic layer 27 and the magnetic moment of the second fixed magnetic layer 25 is directed rightward in the figure.

As shown in FIG. 3, the sense current 113 flows in the X direction in the figure. According to the right-hand rule, the sense current magnetic field formed by flowing the sense current 113 is formed clockwise with respect to the paper surface. Since the second pinned magnetic layer 25 and the first pinned magnetic layer 27 are formed above the nonmagnetic conductive layer 24, the second pinned magnetic layer 25
In addition, the sense current magnetic field in the right direction in the drawing (opposite direction to the Y direction in the drawing) enters the first fixed magnetic layer 27 and coincides with the direction of the synthetic magnetic moment. The antiparallel state between the magnetization of the magnetic layer 27 and the magnetization of the second pinned magnetic layer 25 is hard to break.

When the resultant magnetic moment is directed to the left direction in the figure (the direction opposite to the Y direction in the figure), the sense current 113 is caused to flow in the direction opposite to the X direction in the figure, and the sense current 113 is caused to flow. The sense current magnetic field to be formed is generated counterclockwise with respect to the plane of the paper, and the direction of the combined magnetic moment of the first pinned magnetic layer 27 and the second pinned magnetic layer 25 must match the direction of the sense current magnetic field. There is.

The spin-valve thin film element shown in FIG. 5 has a first fixed magnetic layer (lower) 32
(Upper) 43 and second pinned magnetic layer (lower) 34, (upper) 41
Is formed on the dual spin-valve thin film element.
In this dual spin-valve thin film element, the first fixed magnetic layer (lower) 3 is formed such that the combined magnetic moments formed above and below the free magnetic layer 36 are directed in opposite directions.
2, the direction and magnitude of the magnetic moment of (upper) 43 and the direction and magnitude of the magnetic moment of the second pinned magnetic layers (lower) 34 and (upper) 41 must be controlled.

As shown in FIG. 5, the magnetic moment of the second fixed magnetic layer (lower) 34 formed below the free magnetic layer 36 is the magnetic moment of the first fixed magnetic layer (lower) 32. The magnetic moment of the second pinned magnetic layer (lower) 34 is directed rightward in the figure (Y direction in the figure). Accordingly, the magnetic moment of the first pinned magnetic layer (lower) 32 and the second pinned magnetic layer (lower)
The combined magnetic moment, which can be obtained by adding the magnetic moments of FIG. 34, is directed rightward in the figure (Y direction in the figure). The magnetic moment of the first pinned magnetic layer (upper) 43 formed above the free magnetic layer 36 is larger than the magnetic moment of the second pinned magnetic layer (upper) 41, and The magnetic moment of the magnetic layer (upper) 43 is directed to the left direction in the drawing (the direction opposite to the Y direction in the drawing). Therefore, the combined magnetic moment, which can be obtained by adding the magnetic moment of the first pinned magnetic layer (upper) 43 and the magnetic moment of the second pinned magnetic layer (upper) 41, is the left direction in the figure (the Y direction in the figure). (Opposite direction). Thus, in the present invention, the combined magnetic moments formed above and below the free magnetic layer 36 face in opposite directions.

In the present invention, as shown in FIG. 5, the sense current 114 flows in a direction opposite to the X direction shown. As a result, a sense current magnetic field formed by passing the sense current 114 is formed counterclockwise with respect to the plane of the drawing.

The resultant magnetic moment formed below the free magnetic layer 36 is rightward in the figure (Y direction in the figure).
Since the combined magnetic moment formed above the free magnetic layer 36 is directed to the left direction in the drawing (the direction opposite to the Y direction in the drawing), the directions of the two combined magnetic moments are the same as the direction of the sense current magnetic field. The first pinned magnetic layer (lower) 32 formed under the free magnetic layer 36
, And the magnetization of the second fixed magnetic layer (lower) 34 in an antiparallel state, and the magnetization of the first fixed magnetic layer (upper) 43 formed above the free magnetic layer 36 and the second fixed magnetic layer. (Top) 4
It is possible to keep the antiparallel state of magnetization 1 thermally stable.

Note that the resultant magnetic moment formed below the free magnetic layer 36 is directed leftward in the figure.
When the combined magnetic moment formed above the free magnetic layer 36 is directed rightward in the figure, the sense current 1
14, the direction of the sense current magnetic field formed by flowing the sense current and the direction of the resultant magnetic moment need to match.

In FIGS. 7 and 9, a spin-valve thin-film element in which a free magnetic layer is divided into two layers, a first free magnetic layer and a second free magnetic layer, via a non-magnetic intermediate layer. 7, the first fixed magnetic layer 52 and the second fixed magnetic layer 54 are formed below the nonmagnetic conductive layer 55 as in the spin-valve thin film element shown in FIG. In this case, the same sense current direction control as in the case of the spin-valve thin film element shown in FIG. 1 may be performed. In the case where the first fixed magnetic layer 79 and the second fixed magnetic layer 77 are formed above the nonmagnetic conductive layer 76 as in the spin-valve thin film element shown in FIG. Control of the sense current direction may be performed in the same manner as in the case of the spin-valve thin film element shown in FIG.

As described above, according to the present invention, the direction of the sense current magnetic field formed by passing the sense current, the magnetic moment of the first fixed magnetic layer, and the magnetic moment of the second fixed magnetic layer are added. By matching the direction of the resultant magnetic moment that can be obtained by matching, the exchange coupling magnetic field (RKKY interaction) acting between the first fixed magnetic layer and the second fixed magnetic layer is amplified, and The antiparallel state (ferri state) of the magnetization of the first fixed magnetic layer and the magnetization of the second fixed magnetic layer can be kept thermally stable.

In particular, in the present invention, in order to further improve the thermal stability, an antiferromagnetic material having a high blocking temperature such as a PtMn alloy is used for the antiferromagnetic layer. However, even if the magnetization of the first fixed magnetic layer is significantly increased, the antiparallel state (ferri state) of the magnetization of the first fixed magnetic layer and the magnetization of the second fixed magnetic layer can be hardly broken.

If the sense output is increased by increasing the amount of the sense current in order to cope with the increase in the recording density, the sense current magnetic field also increases accordingly. In the present invention, however, the sense current magnetic field is set to the first level. Since the effect of amplifying the exchange coupling magnetic field acting between the fixed magnetic layer and the second fixed magnetic layer is brought about, the magnetization state of the first fixed magnetic layer and the second fixed magnetic layer is increased by increasing the sense current magnetic field. Becomes more stable.

The control of the sense current direction can be applied to any antiferromagnetic layer using any antiferromagnetic material. For example, the antiferromagnetic layer and the fixed magnetic layer (the first fixed magnetic layer) may be used. Exchange magnetic field (exchange anisotropic magnetic field) at the interface with
It does not matter whether a heat treatment is necessary or not in order to generate.

Further, even in the case of a single spin-valve thin film element in which the pinned magnetic layer is formed as a single layer as in the prior art, the direction of the sense current magnetic field formed by flowing the above-described sense current is also considered. By making the magnetization direction of the pinned magnetic layer coincide with that of the pinned magnetic layer, the magnetization of the pinned magnetic layer can be thermally stabilized.

[0250]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a spin-valve type thin film element is used in which a fixed magnetic layer is divided into a first fixed magnetic layer and a second fixed magnetic layer via a non-magnetic intermediate layer. And
A film thickness ratio between the first fixed magnetic layer and the second fixed magnetic layer,
The relationship between the exchange coupling magnetic field (Hex) and ΔMR (resistance change rate) was measured. First, the first fixed magnetic layer (the fixed magnetic layer on the side in contact with the antiferromagnetic layer) is fixed at 20 Å or 40 Å, and the film thickness of the second fixed magnetic layer is changed. The relationship between the thickness of the magnetic layer and the exchange coupling magnetic field and ΔMR was examined.
The film configuration used in the experiment is as follows. Si substrate /
Alumina / Ta (30) / antiferromagnetic layer; PtMn (15
0) / first fixed magnetic layer; Co (20 or 40) / nonmagnetic intermediate layer; Ru (7) / second fixed magnetic layer; Co (X)
/ Nonmagnetic conductive layer; Cu (25) / Free magnetic layer; Co
(10) + NiFe (40) / Ta (30). The numerical value in parentheses in each layer indicates the film thickness, and the unit is angstrom.

In the present invention, the spin-valve type thin film
After forming the device, a magnetic field of 200 (Oe) is applied.
At 260 ° C. for 4 hours. The experimental results
It is shown in FIG. 14 and FIG. As shown in FIG.
The thickness t of the fixed magnetic layer (P1)_P120 angstroms
, The film thickness t of the second pinned magnetic layer (P2)_P2
At 20 Å, the exchange coupling
The field (Hex) decreases and the film thickness t _P2Thicken
As a result, the exchange coupling magnetic field gradually decreases.
I understand. The thickness of the first pinned magnetic layer (P1)
t_P1Is fixed at 40 Å, the second
Thickness t of constant magnetic layer (P2)_P2To 40 angstroms
Then, the exchange coupling magnetic field decreases rapidly and the film thickness t_P2
Larger than 40 angstroms,
It can be seen that the exchange coupling magnetic field decreases. Also, the film
Thickness t_P2Smaller than 40 angstroms
And the exchange coupling magnetic field is large up to about 26 Å
The film thickness t_P2Than 26 angstroms
As the size decreases, the exchange coupling magnetic field decreases.
I understand.

[0252] By the way when the film thickness t _P1 of the first pinned magnetic layer (P1) and the thickness t _P2 of the second pinned magnetic layer (P2) are formed substantially the same thickness, rapidly exchange coupling magnetic field Is decreased because the magnetization of the first pinned magnetic layer (P1) and the magnetization of the second pinned magnetic layer (P2) are not magnetized antiparallel to each other, that is, it is unlikely to be in a so-called ferri-state. Guessed. As shown in the above-described film configuration, both the first pinned magnetic layer (P1) and the second pinned magnetic layer (P2)
Since they are formed of an o film, they have the same saturation magnetization (Ms). Furthermore, by being formed with substantially the same thickness, the magnetic moment (Ms) of the first pinned magnetic layer (P1)
.T _P1 ) and the magnetic moment (Ms · t _P2 ) of the second pinned magnetic layer (P2) are set to be substantially the same. In the present invention, since the PtMn alloy is used for the antiferromagnetic layer, an exchange coupling magnetic field is generated at the interface with the first fixed magnetic layer (P1) by performing annealing in a magnetic field after film formation,
The first pinned magnetic layer (P1) is to be fixed in a certain direction.

However, if the magnetic moments of the first pinned magnetic layer (P1) and the second pinned magnetic layer (P2) are almost the same value, the first pinned magnetic layer (P2) will not be able to perform the heat treatment by applying a magnetic field. Fixed magnetic layer (P1) and second fixed magnetic layer (P2)
Both try to move in the direction of the magnetic field. Originally, an exchange coupling magnetic field (RKKY interaction) is generated between the first fixed magnetic layer (P1) and the second fixed magnetic layer (P2), and the first fixed magnetic layer (P1) The magnetization and the magnetization of the second pinned magnetic layer (P2) tend to be magnetized in an antiparallel state (ferri state), but the magnetization of the first pinned magnetic layer (P1) and the second pinned magnetic layer (P2) Since the magnetizations are directed to each other in the direction of the magnetic field, they are hardly magnetized in an antiparallel state, and the magnetization states of the first fixed magnetic layer (P1) and the second fixed magnetic layer (P2) are
It is in a very unstable state against an external magnetic field or the like.

For this reason, it is preferable to make a certain difference between the magnetic moment of the first pinned magnetic layer (P1) and the magnetic moment of the second pinned magnetic layer (P2).
As shown, the first difference in the film thickness t _P2 is too large for fixed magnetic layer thickness t _P1 and the second fixed magnetic layer (P1) (P2), the first pinned magnetic layer (P1) If the magnetic moment of the second pinned magnetic layer (P2) is too large, the exchange coupling magnetic field is reduced, and the antiparallel state is easily broken.

FIGS. 16 and 17 show the second pinned magnetic layer (P
The thickness t _{P2 of} 2) is fixed at 30 angstroms,
When the film thickness t _P1 of the fixed magnetic layer (P1) is changed,
The thickness t _{P1 of} the first pinned magnetic layer and the exchange coupling magnetic field (He
3 is a graph showing a relationship between x) and ΔMR. The film configuration of the spin-valve thin film element used in this experiment is as follows. Si substrate / Alumina / Ta (30) / PtM
n (150) / first fixed magnetic layer; Co (X) / nonmagnetic intermediate layer; Ru (7) / second fixed magnetic layer; Co (30)
/ Nonmagnetic conductive layer; Cu (25) / Free magnetic layer; Co
(10) + NiFe (40) / Ta (30). The numerical value in parentheses in each layer indicates the film thickness, and the unit is angstrom. In the present invention, after forming the spin-valve thin film element, a heat treatment was performed at 260 ° C. for 4 hours while applying a magnetic field of 200 (Oe).

As shown in FIG. 16, when the thickness t _P1 of the first pinned magnetic layer (P1) is set to 30 Å, ie, the same thickness t _P2 as the thickness of the second pinned magnetic layer (P2). It can be seen that the exchange coupling magnetic field (Hex) drops sharply when formed. This is for the reason described above.

Also, the thickness t of the first pinned magnetic layer (P1)
_It can be seen that the exchange coupling magnetic field is also small when _P1 is about 32 Å. This is because the magnetic film thickness of the first pinned magnetic layer is reduced to the actual film thickness t due to the generation of the thermal diffusion layer.
_{P1 and} the thickness t _{P2 of} the second pinned magnetic layer (=
30 Angstroms).

The heat diffusion layer is formed by diffusing a metal element at the interface between the antiferromagnetic layer and the first pinned magnetic layer. The heat diffusion layer has a film structure used in this experiment. As shown in (1), it is likely to occur when the antiferromagnetic layer and the fixed magnetic layer are formed below the free magnetic layer.

FIG. 18 shows the fabrication of a dual spin-valve thin film element, and FIG.
The thickness of the first pinned magnetic layer when both of the two pinned magnetic layers are fixed at 20 Å and the thickness of each of the two first pinned magnetic layers is changed;
4 is a graph showing a relationship with an exchange coupling magnetic field (Hex).
The film configuration of the spin-valve thin film element used in this experiment is as follows. Si substrate / Alumina / Ta (30)
/ Antiferromagnetic layer; PtMn (150) / first pinned magnetic layer (below P1); Co (X) / nonmagnetic intermediate layer; Ru (6)
/ Second pinned magnetic layer (under P2); Co (20) / non-magnetic conductive layer; Cu (20) / free magnetic layer; Co (10)
+ NiFe (40) + Co (10) / nonmagnetic conductive layer; C
u (20) / second pinned magnetic layer (on P2); Co (2
0) / nonmagnetic intermediate layer; Ru (8) / first pinned magnetic layer (on P1); Co (X) / antiferromagnetic layer; PtMn (1
50) / Protective layer; Ta (30). The numerical value in parentheses in each layer indicates the film thickness, and the unit is angstrom. In the present invention, after forming the spin-valve thin film element, a heat treatment was performed at 260 ° C. for 4 hours while applying a magnetic field of 200 (Oe).

In the experiment, the first pinned magnetic layer (below P1) formed below the free magnetic layer was fixed at 25 Å, and the first pinned magnetic layer formed above the free magnetic layer was fixed at 25 Å. The thickness of the fixed magnetic layer (on P1) was changed, and the relationship between the thickness of the first fixed magnetic layer (on P1) and the exchange coupling magnetic field (Hex) was examined. Further, the first fixed magnetic layer (above P1) formed above the free magnetic layer is fixed at 25 Å, and the first fixed magnetic layer (P1) formed below the free magnetic layer is fixed.
1 below) to change the thickness of the first pinned magnetic layer (P
1) The relationship between the film thickness and the exchange coupling magnetic field was examined.

As shown in FIG. 18, the first pinned magnetic layer (under P1) is fixed at 25 angstroms, and as the film thickness of the first pinned magnetic layer (over P1) approaches 20 angstroms, it gradually increases. When the thickness of the first pinned magnetic layer (on P1) becomes about 18 to 22 Å, the exchange coupling magnetic field becomes almost the same as that of the second pinned magnetic layer (on P1). Because it becomes film thickness,
For the above-mentioned reason, the exchange coupling magnetic field decreases rapidly. It can also be seen that as the thickness of the first pinned magnetic layer (above P1) is gradually increased from 22 Å to 30 Å, the exchange coupling magnetic field is gradually reduced.

As shown in FIG. 18, when the first pinned magnetic layer (above P1) is fixed at 25 angstroms 7 and the thickness of the first pinned magnetic layer (below P1) approaches 20 angstroms, gradually However, when the thickness of the first pinned magnetic layer (below P1) becomes about 18 to 22 angstroms, the exchange coupling magnetic field rapidly decreases. Further, the first fixed magnetic layer (P1
It can be seen that when the film thickness in the lower section is larger than 22 Å, the exchange coupling magnetic field increases up to the film thickness of about 26 Å, but when the film thickness is 26 Å or more, the exchange coupling magnetic field decreases.

Here, when the film thickness of the first fixed magnetic layer (P1) is set to about 22 Å, the exchange coupling magnetic field in the first fixed magnetic layer (on P1) and the first fixed magnetic layer Comparing with the exchange coupling magnetic field at (P1 bottom), the film thickness of the first pinned magnetic layer (P1 top)
It can be seen that the exchange coupling magnetic field can be larger when the thickness is set to about Å than when the first pinned magnetic layer (below P1) is set to about 22 Å.
This is, as described above, the first pinned magnetic layer (below P1).
Since a thermal diffusion layer is easily formed at the interface between the first fixed magnetic layer and the antiferromagnetic layer, the magnetic thickness of the first fixed magnetic layer becomes substantially small, and the second fixed magnetic layer (P2 This is because the film thickness becomes substantially the same as the film thickness in the lower part).

As described above, according to the experimental results shown in FIGS. 14, 16 and 18, in the present invention, an exchange coupling magnetic field of 500 (Oe) or more can be obtained (the first fixed magnetic layer (P
The thickness of 1) / (the thickness of the second pinned magnetic layer (P2)) was examined. First, as shown in FIG. 14, when the first pinned magnetic layer (P1) is fixed at 20 angstroms,
In order to obtain an exchange coupling magnetic field of 0 (Oe) or more, (the thickness of the first fixed magnetic layer (P1)) / (the second fixed magnetic layer (P
It can be seen that the film thickness 2) must be 0.33 or more and 0.91 or less or 1.1 or more. At this time, the thickness of the second fixed magnetic layer (P2) is 10 to 6
0 angstrom (excluding 18 to 22 angstrom).

Next, as shown in FIG. 14, when the first pinned magnetic layer (P1) is fixed at 40 Å,
In order to obtain an exchange coupling magnetic field of 00 (Oe) or more, the thickness of the first fixed magnetic layer (P1) / (the thickness of the second fixed magnetic layer (P1))
2) 0.55 to 0.95, 1.05
It is understood that the number must be set to 4 or less. At this time, the thickness of the second fixed magnetic layer (P2) is 10 to 6
0 angstrom (excluding 38-42 angstrom).

Next, as shown in FIG. 16, when the second pinned magnetic layer (P2) is fixed at 30 Å,
To obtain an exchange coupling magnetic field of 500 (Oe) or more, (first
(Thickness of fixed magnetic layer (P1)) / (thickness of second fixed magnetic layer (P2)) must be 0.33 or more and 0.93 or less, or 1.06 or more and 2.33 or less. You can see that. In this case, the first pinned magnetic layer (P1)
Is in the range of 10 to 70 Å (excluding 28 to 32 Å).

Further, as shown in FIG. 18, in the case of a dual spin-valve thin film element, (film thickness of first fixed magnetic layer (P1)) / (film thickness of second fixed magnetic layer (P2)) It can be seen that if the thickness is out of the range of 0.9 or more and 1.1 or less, an exchange coupling magnetic field of 500 (Oe) or more can be obtained. Here, taking the range of the widest film thickness ratio in which exchange coupling of 500 (Oe) or more can be obtained, (film thickness of first fixed magnetic layer (P1)) / (second fixed magnetic layer (P2) ) Is in the range of 0.33 to 0.95, or 1.05 to 4.

However, the exchange coupling magnetic field is not limited to the film thickness ratio, but also the first fixed magnetic layer (P1) and the second fixed magnetic layer (P1).
Since the film thickness of 2) is also one of the important factors, the film thickness of the first fixed magnetic layer (P
1) and the thickness of the second pinned magnetic layer (P2)
The thickness of the first fixed magnetic layer (P1) is set within the range of 0 to 70 angstroms, and the second fixed magnetic layer (P2)
If the absolute value obtained by subtracting the film thickness is 2 Å or more, an exchange coupling magnetic field of 500 (Oe) or more can be obtained.

Next, in the present invention, an exchange coupling magnetic field of 1000 (Oe) or more can be obtained (film thickness of first fixed magnetic layer (P1)) / (film of second fixed magnetic layer (P2)). Thickness). First, as shown in FIG. 14, when the thickness of the first pinned magnetic layer (P1) is set to 20 Å, (film thickness of the first pinned magnetic layer (P1)) / (film thickness of the second pinned magnetic layer (P2)) 0.53 to 0.91 or 1.
If it is set to 1 or more, an exchange coupling magnetic field of 1000 (Oe) or more can be obtained. At this time, the thickness of the second pinned magnetic layer (P2) is 10 to 38 angstroms (1
(Excluding 8 to 22 angstroms). Further, as shown in FIG. 14, the first pinned magnetic layer (P1) is
When the thickness is set to 0 angstroms, (the thickness of the first fixed magnetic layer (P1)) / (the thickness of the second fixed magnetic layer (P2)) is 0.88 to 0.95, or 1.05 to 1 .8
Within this range, an exchange coupling magnetic field of 1000 (Oe) or more can be obtained. At this time, the thickness of the second pinned magnetic layer (P2) is in the range of 22 to 45 angstroms (excluding 38 to 42 angstroms). Further, as shown in FIG. 16, the second pinned magnetic layer (P
2) is fixed to 30 angstroms, (film thickness of first fixed magnetic layer (P1)) / (second fixed magnetic layer (P1)
2) 0.56 to 0.93 or 1.06
An exchange coupling magnetic field of 1000 (Oe) or more can be obtained within the range of 1.6 to 1.6. In this case, the first
The thickness of the fixed magnetic layer (P1) is in the range of 10 to 50 angstroms (excluding 28 to 32 angstroms).

As shown in FIG. 18, in the case of a dual spin-valve thin film element, (thickness of first fixed magnetic layer (P1)) / (thickness of second fixed magnetic layer (P2)) If the thickness is in the range of about 0.5 to 0.9 or 1.1 to 1.5, an exchange coupling magnetic field of 1000 (Oe) or more can be obtained. Therefore, 1000 (O
e) To obtain the above exchange coupling magnetic field, the thickness of the first fixed magnetic layer (P1) / (the thickness of the second fixed magnetic layer (P2)) is set to 0.53 to 0.95, Alternatively, 1.05-1.
8, the first fixed magnetic layer (P1) and the second fixed magnetic layer (P2) have a thickness in the range of 10 to 50 angstroms, and the first fixed magnetic layer (P1).
It is preferable that the absolute value obtained by subtracting the film thickness of the second pinned magnetic layer (P2) from the film thickness of 2 Å is 2 Å or more.
As shown in FIG. 15 and FIG. 17, if the thickness ratio and the thickness are within the above-described ranges, ΔMR does not decrease so much.
It is possible to obtain a ΔMR of about 6% or more. This ΔM
The value of R is about the same as or slightly lower than ΔMR of the conventional spin-valve thin film element (limited to a single spin-valve thin film element).

As shown in FIG. 15, when the first pinned magnetic layer (P1) is set to 40 Å, ΔMR is slightly smaller than when the second pinned magnetic layer (P1) is set to 20 Å. It turns out that it becomes. The first pinned magnetic layer (P1) is a layer that does not actually participate in ΔMR, and the ΔMR is the second pinned magnetic layer (P1).
It is determined by the relationship between the fixed magnetization of 2) and the fluctuating magnetization of the free magnetic layer. However, since the sense current also flows through the first pinned magnetic layer (P1) that is not involved in ΔMR, a so-called shunt loss (shunt loss) occurs. The larger the thickness, the larger. For the above reasons, ΔMR tends to decrease as the thickness of the first pinned magnetic layer (P1) increases.

Next, the appropriate thickness of the non-magnetic intermediate layer formed between the first pinned magnetic layer (P1) and the second pinned magnetic layer (P2) was measured. In the experiment, a bottom type in which an antiferromagnetic layer was formed below the free magnetic layer,
Two types of top-valve spin-valve thin film elements having an antiferromagnetic layer formed above the free magnetic layer were fabricated, and the relationship between the thickness of the nonmagnetic intermediate layer and the exchange coupling magnetic field was examined. The film configuration of the bottom-type spin-valve thin film element used in the experiment is as follows: Si substrate / alumina / Ta (3
0) / antiferromagnetic layer; PtMn (200) / first pinned magnetic layer; Co (20) / non-magnetic intermediate layer; Ru (X) / second
Fixed magnetic layer; Co (25) / nonmagnetic conductive layer; Co (1
0) / free magnetic layer; Co (10) + NiFe (40)
/ Ta (30), and the film configuration of the top spin-valve thin film element is as follows: Si substrate / alumina / Ta
(30) / free magnetic layer; NiFe (40) + Co (1
0) / nonmagnetic conductive layer; Cu (25) / second fixed magnetic layer; Co (25) / nonmagnetic intermediate layer; Ru (X) / first fixed magnetic layer; Co (20) / antiferromagnetic Layer; PtMn (2
00) / Ta (30). The numerical value in parentheses indicates the film thickness, and the unit is angstrom. After forming each spin-valve thin film element, a heat treatment is performed at 260 ° C. for 4 hours while applying a magnetic field of 200 (Oe). FIG. 19 shows the experimental results. As shown in FIG. 19, the behavior of the exchange coupling magnetic field with respect to the thickness of the Ru film (nonmagnetic intermediate layer) is significantly different between the top type and the bottom type.

In the present invention, a range in which an exchange coupling magnetic field of 500 (Oe) or more can be obtained is preferable.
Ru capable of obtaining an exchange coupling magnetic field of 0 (Oe) or more
It can be seen that the thickness of the film is in the range of 2.5 to 6.4 angstroms, or 6.6 to 10.7 angstroms. More preferably, it is within a range where an exchange coupling magnetic field of 1000 (Oe) or more can be obtained, and the thickness of the Ru film is 2.8 to 6.2 angstroms, or 6.
Within the range of 8 to 10.3 angstroms, 10
It can be seen that an exchange coupling magnetic field of 00 (Oe) or more can be obtained.

Next, in the bottom-type spin-valve thin film element, the thickness of the Ru film capable of obtaining an exchange coupling magnetic field of 500 (Oe) or more is in the range of 3.6 to 9.6 angstroms. You can see that. In addition, 4.0
Within the range of 9.4 angstroms, 1000
It becomes possible to obtain an exchange coupling magnetic field of (Oe) or more.
By the way, the suitable thickness range of the non-magnetic intermediate layer differs between the top type spin valve thin film element and the bottom type spin valve thin film element because the first fixed magnetic layer and the second
Exchange magnetic field (RKKY) acting between the
It is presumed that the interaction is very sensitive to a change in the lattice constant of the underlying film or a change in the value of the energy band of conduction electrons in the magnetic layer.

Next, in the present invention, four types of spin-valve thin film elements (single spin-valve thin film elements) were manufactured, and the antiferromagnetic layer (PtMn) of each spin-valve thin film element was manufactured.
Alloy) and the exchange coupling magnetic field. Examples 1 and 2 are spin-valve thin film elements in which a fixed magnetic layer is divided into two layers, a first fixed magnetic layer and a second fixed magnetic layer, via a nonmagnetic intermediate layer. And a conventional spin-valve thin-film element in which a fixed magnetic layer is formed as a single layer.

First, the spin-valve thin film element of Example 1 is a top type in which an antiferromagnetic layer is formed above a free magnetic layer, and the film configuration is from the bottom: Si substrate / alumina / Ta (30) / Free magnetic layer; NiFe (40) + C
o (10) / non-magnetic conductive layer; Cu (25) / second fixed magnetic layer; Co (25) / non-magnetic intermediate layer; Ru (4) / first fixed magnetic layer; Co (20) / anti-magnetic layer Ferromagnetic layer; PtMn
(X) / Ta (30), and the spin-valve thin film element of Example 2 is a bottom type in which an antiferromagnetic layer is formed below the free magnetic layer. Si
Substrate / alumina / Ta (30) / antiferromagnetic layer; PtMn
(X) / first fixed magnetic layer; Co (20) / non-magnetic intermediate layer; Ru (8) / second fixed magnetic layer; Co (25) / non-magnetic conductive layer; Cu (25) / free magnetic Layer; Co (1
0) + NiFe (40) / Ta (30).

The spin-valve thin-film element of Comparative Example 1 is of a top type in which an antiferromagnetic layer is formed above a free magnetic layer, and the film configuration is Si substrate / alumina / Ta (30) / Free magnetic layer; NiFe (40) + C
o (10) / nonmagnetic conductive layer; Cu (25) / pinned magnetic layer; Co (40) / antiferromagnetic layer; PtMn (X) / Ta
(30), and the spin-valve thin film element of Comparative Example 2 is a bottom type in which an antiferromagnetic layer is formed below the free magnetic layer, and the film configuration is Si substrate / alumina / Ta (30) / antiferromagnetic layer; PtMn (X) / pinned magnetic layer; Co (40) / nonmagnetic conductive layer; Cu (25) /
Free magnetic layer; Co (10) + NiFe (40) / Ta
(30). In the film configuration of each spin-valve thin film element, the numerical value in parentheses indicates the film thickness, and the unit is angstrom.

Further, in the present invention, after the spin-valve thin film element is formed, the magnetic field of 200 (Oe) in Examples 1 and 2, and the magnetic field of 2 k (Oe) in Comparative Examples 1 and 2 While applying a heat treatment at 260 ° C. for 4 hours. FIG. 20 shows the experimental results. As shown in FIG. 20, all of the four types of spin-valve thin-film elements are PtMn.
It can be seen that the exchange coupling magnetic field can be increased by increasing the thickness of the alloy. Here, in the present invention, 500 (O
e) Since the range in which the above exchange coupling magnetic field can be obtained is a preferable range, in both Comparative Examples 1 and 2, unless the thickness of the PtMn alloy is at least 200 Å or more, the exchange coupling of 500 (Oe) or more is required. It turns out that a magnetic field cannot be obtained.

On the other hand, in Examples 1 and 2, PtMn
500 if the thickness of the alloy is 90 Å or more
It can be seen that an exchange coupling magnetic field of (Oe) or more can be obtained. Therefore, in the present invention, the preferable thickness range of the PtMn alloy is set in the range of 90 to 200 angstroms. Further, as shown in FIG. 20, it is understood that if the thickness of the PtMn alloys of Examples 1 and 2 is set to 100 Å or more, an exchange coupling magnetic field of at least 1000 (Oe) can be obtained. Therefore, in the present invention, a more preferable thickness of the PtMn alloy is set to 100 to
It is set within the range of 200 angstroms.

Next, in the present invention, two types of dual spin-valve thin film elements were manufactured, and the relationship between the thickness of the antiferromagnetic layer (PtMn alloy) and the exchange coupling magnetic field in each spin-valve thin film element was measured. did. The embodiment is a dual spin-valve thin film element according to the present invention in which a fixed magnetic layer is divided into two layers, a first fixed magnetic layer and a second fixed magnetic layer, via a non-magnetic intermediate layer. Is a conventional dual spin-valve thin film element in which a fixed magnetic layer is formed as a single layer.

First, the film configuration of the spin-valve type thin film element of the embodiment is as follows: from the bottom, Si substrate / alumina / Ta (3
0) / antiferromagnetic layer; PtMn (x) / first fixed magnetic layer; Co (20) / nonmagnetic intermediate layer; Ru (6) / second fixed magnetic layer; Co (25) / nonmagnetic conductive Layer; Cu (2
0) / free magnetic layer; Co (10) + NiFe (40)
+ Co (10) / nonmagnetic conductive layer; Cu (20) / second pinned magnetic layer; Co (20) / nonmagnetic intermediate layer; Ru (8)
/ First pinned magnetic layer; Co (25) / antiferromagnetic layer; Pt
Mn (X) / Ta (30), and the film configuration of the spin-valve thin film element of the comparative example is, from the bottom, Si substrate / alumina / Ta (30) / antiferromagnetic layer; PtMn (X) /
Fixed magnetic layer; Co (30) / nonmagnetic conductive layer; Cu (2
0) / free magnetic layer; Co (10) + NiFe (40)
+ Co (10) / nonmagnetic conductive layer; Cu (20) / pinned magnetic layer; Co (30) / antiferromagnetic layer; PtMn (X) / T
a (30). The numerical value in parentheses in the film configuration of each spin-valve thin film element indicates the film thickness, and the unit is angstrom.

After forming each spin-valve thin film element,
In the example, a magnetic field of 200 (Oe) was used, and in the comparative example, 2 k
Heat treatment is performed at 260 ° C. for 4 hours while applying a magnetic field of (Oe). FIG. 21 shows the experimental results. FIG.
As shown in the figure, in the comparative example, the thickness of the PtMn alloy was set to about 20
If it is not formed at 0 Å or more, 500 (O
e) It can be seen that the above exchange coupling magnetic field cannot be obtained. In contrast, in the embodiment, the thickness of the PtMn alloy is
If formed at 100 Å or more, 500 (O
e) It can be seen that the above exchange coupling magnetic field can be obtained.
Therefore, in the present invention, the preferable thickness of the antiferromagnetic layer is set to 100
It is set within the range of ~ 200 angstroms. Further, in the embodiment, if the PtMn alloy is formed to have a thickness of 110 Å or more, an exchange coupling magnetic field of 1000 (Oe) or more can be obtained.
The more preferable thickness of the antiferromagnetic layer is set in the range of 110 to 200 angstroms.

FIG. 22 shows the thickness of the PtMn alloy, Δ
It is a graph which shows the relationship with MR. As shown in FIG. 22, in the comparative example, when the thickness of the PtMn alloy is 200 Å or more, ΔMR of about 10% or more can be obtained.
It can be seen that even when the film thickness of the Mn alloy is reduced to about 100 Å, a ΔMR of about the same level as in the related art can be secured.

By the way, of the laminated films in the spin-valve type thin film element, the thickest is the antiferromagnetic layer. Therefore, according to the present invention, as shown in FIGS. 20 and 21, even if the thickness of the antiferromagnetic layer is reduced, specifically, the film of the antiferromagnetic layer of the conventional spin-valve thin film element is formed. Even when formed with half or less of the thickness, a large exchange coupling magnetic field can be obtained. Therefore, according to the present invention, the entire film thickness of the spin-valve type thin film element can be reduced.
As shown in FIG. 3, even if the thickness of the gap layers 121 and 125 formed above and below the spin-valve thin film element 122 is made sufficiently large to ensure insulation, the gap length G
1 can be reduced, and the gap can be reduced.

Next, a spin-valve thin film element according to the present invention, in which the free magnetic layer was divided into two layers, a first free magnetic layer and a second free magnetic layer, via a non-magnetic intermediate layer, was manufactured. The relationship between the thickness ratio between the first free magnetic layer and the second free magnetic layer and the exchange coupling magnetic field was measured. First, a first free magnetic layer (in contact with the nonmagnetic conductive layer,
The thickness of the free magnetic layer on the side directly involved in ΔMR is 50
Fixed with angstrom and a second free magnetic layer (ΔM
The thickness of the free magnetic layer (the side not directly involved in R) was changed. The film structure is as follows: Si substrate / alumina / Ta (3
0) / second free magnetic layer (F2); NiFe (X) /
Non-magnetic intermediate layer; Ru (8) / first free magnetic layer (F
1); NiFe (40) + Co (10) / nonmagnetic conductive layer; Cu (20) / Ru (8) / antiferromagnetic layer; PtMn
(150) / Ta (30), and the numerical value in parentheses in each layer indicates the film thickness, and the unit is angstrom. After forming the spin-valve thin film element, 200
The heat treatment is performed at 260 ° C. for 4 hours while applying the (Oe) magnetic field.

As shown in FIG. 23, when the thickness of the second free magnetic layer (F2) is increased to about 40 Å, the exchange coupling magnetic field is increased. Further, it can be seen that when the thickness of the second free magnetic layer (F2) becomes 60 Å or more, the exchange coupling magnetic field gradually decreases. The second free magnetic layer (F
When the film thickness in 2) was in the range of 40 to 60 Å, the exchange coupling magnetic field was rapidly reduced, and measurement was impossible. The reason is that the film thickness of the first free magnetic layer (F1) (= 50 Å) and the film thickness of the second free magnetic layer become almost the same value, so that the first free magnetic layer (F1) ) And the second free magnetic layer (F2) have substantially the same magnetic moment, and the magnetization of the first free magnetic layer (F1) and the magnetization of the second free magnetic layer (F2) change with respect to the applied magnetic field. Both attempt to move in the direction of the applied magnetic field. If the values of the magnetic moments are different, an exchange coupling magnetic field (RKKY interaction) is generated between the first free magnetic layer (F1) and the second free magnetic layer (F2), and the first free magnetic layer The magnetization of the layer (F1) and the second free magnetic layer (F1)
As described above, the magnetization of the first free magnetic layer (F1) and the magnetization of the second free magnetic layer (F2) are both in the same direction. , The magnetization states of the first free magnetic layer (F1) and the second free magnetic layer (F2) are destabilized, and as described later, the second free magnetic layer (F2)
, And the relative angle between the fixed magnetization of the fixed magnetic layer (the first fixed magnetic layer) and the fixed magnetization of the fixed magnetic layer cannot be controlled, and ΔMR sharply decreases.

In the present invention, the range in which an exchange coupling magnetic field of 500 (Oe) or more can be obtained is set as a preferable range. Therefore, as shown in FIG. 23, the film thickness of the first free magnetic layer (F1) If the (thickness) / (thickness of the second free magnetic layer (F2)) is formed in the range of 0.56 to 0.83, or 1.25 to 5, the exchange coupling magnetic field of 500 (Oe) or more Can be obtained. Further, the (thickness of first free magnetic layer (F1) / second free magnetic layer (F1)
2) is 0.61 to 0.83, or 1.2
It is more preferable that the thickness be in the range of 5 to 2.1, since an exchange coupling magnetic field of 1000 (Oe) or more can be obtained.

Next, according to the present invention, the spin-valve thin film element according to the present invention in which the free magnetic layer is divided into two layers of a first free magnetic layer and a second free magnetic layer via a non-magnetic intermediate layer. Was manufactured, and the relationship between the thickness ratio between the first free magnetic layer and the second free magnetic layer and ΔMR was measured. First, the second free magnetic layer (the free magnetic layer not directly involved in ΔMR) is fixed at 20 Å, and the first free magnetic layer (the non-magnetic conductive layer is contacted with the ΔM
The thickness of the free magnetic layer on the side directly involved in R was changed. The film configuration is as follows: Si substrate / alumina / Ta (3
0) / second free magnetic layer; NiFe (20) / nonmagnetic intermediate layer; Ru (8) / first free magnetic layer; NiFe
(X) + Co (10) / nonmagnetic conductive layer; Cu (20) /
First pinned magnetic layer; Co (25) / nonmagnetic intermediate layer; Ru
(8) / second pinned magnetic layer; Co (20) / antiferromagnetic layer; PtMn (15) / Ta (30), the numerical value in parentheses in each layer indicates the film thickness, and the unit is angstrom. It is.

In the present invention, after the spin-valve thin film element is formed, a heat treatment is performed at 260 ° C. for 4 hours by applying a magnetic field of 200 (Oe). As can be seen from the above film configuration, in the present invention, the first free magnetic layer is formed of two layers, and the thickness of the NiFe film is changed. The experimental results are shown in FIG. 24. The horizontal axis shown in FIG.
This is the total thickness of the first free magnetic layer obtained by adding the thickness of the iFe alloy and the thickness of the Co film (= 10 angstroms). As shown in FIG. 24, the first free magnetic layer (F1)
When the film thickness of the second free magnetic layer (F2) approaches 20 angstroms, the film thickness becomes approximately the same as the film thickness of the second free magnetic layer (F2).
It can be seen that the MR drops sharply. As shown in FIG. 24, the thickness of the first free magnetic layer (F1) is about 30
When the thickness exceeds angstrom, the ΔMR increases, and it is possible to obtain a ΔMR similar to that of a conventional spin-valve thin film element (single spin-valve thin film element).

By the way, 500 derived from FIG.
It is possible to obtain an exchange coupling magnetic field of (Oe) or more (first
The range of (thickness of free magnetic layer (F1)) / (thickness of second free magnetic layer (F2)) is shown in FIG. 24. By setting (thickness) / (thickness of the second free magnetic layer (F2)) in the range of 1.25 to 5, a high ΔMR can be obtained.

Next, in the present invention, the thickness of the non-magnetic intermediate layer interposed between the first free magnetic layer and the second free magnetic layer is changed to exchange with the thickness of the non-magnetic intermediate layer. The relationship with the coupling magnetic field was measured. The film configuration of the spin-valve thin film element (dual spin-valve thin film element) used in the experiment is as follows: Si substrate / alumina / Ta (30) / antiferromagnetic layer; PtMn (150) / Ru (6) / non Magnetic conductive layer; Cu (20) / first free magnetic layer; Co (1
0) + NiFe (50) / nonmagnetic intermediate layer; Ru (X) /
First free magnetic layer; NiFe (30) + Co (10)
/ Nonmagnetic conductive layer; Cu (20) / Ru (8) / antiferromagnetic layer; PtMn (150) / Ta (30), and the number in parentheses in each layer represents the film thickness, and the unit is Angstroms. It is. In the present invention, after forming a spin-valve thin film element, while applying a magnetic field of 200 (Oe),
The heat treatment is performed at 260 ° C. for 4 hours. FIG. 20 shows the experimental results.

As shown in FIG. 20, in order to obtain an exchange coupling magnetic field of 500 (Oe) or more, the thickness of the Ru film is set to 5.5 to 1
It can be seen that the film should be formed within the range of 0.0 angstroms. Further, it can be seen that in order to obtain an exchange coupling magnetic field of 1000 (Oe) or more, the Ru film should be formed within the range of 5.9 to 9.4 angstroms.

[0293]

According to the present invention described in detail above, the fixed magnetic layer is divided into two layers of a first fixed magnetic layer and a second fixed magnetic layer via a non-magnetic intermediate layer. The exchange coupling magnetic field (RKKY interaction) generated between the first pinned magnetic layer and the second pinned magnetic layer causes the magnetization of the first pinned magnetic layer and the magnetization of the second pinned magnetic layer to be antiparallel. With such a state, the magnetization state of the fixed magnetic layer can be maintained in a very stable state. In particular, in the present invention, the exchange coupling magnetic field of 500 (Oe) or more can be obtained by adjusting the thickness ratio and the film thickness of the first fixed magnetic layer and the second fixed magnetic layer within an appropriate range. Preferably, an exchange coupling magnetic field of 1000 (Oe) or more can be obtained.

In the present invention, the non-magnetic intermediate layer interposed between the first pinned magnetic layer and the second pinned magnetic layer
u, Rh, Ir, Cr, Re, Cu, etc., and the nonmagnetic intermediate layer is formed above the free magnetic layer, and the nonmagnetic intermediate layer is formed below the free magnetic layer. By adjusting the thickness of the non-magnetic intermediate layer within an appropriate range, an exchange coupling magnetic field of 500 (Oe) or more can be obtained, and more preferably, an exchange coupling magnetic field of 1000 (Oe) or more can be obtained. be able to.

Further, in the present invention, the antiferromagnetic layer has a high blocking temperature and a large exchange coupling magnetic field (exchange anisotropic magnetic field) generated at the interface with the fixed magnetic layer (first fixed magnetic layer). Moreover, a PtMn alloy is used as an antiferromagnetic material having excellent corrosion resistance. Or X-Mn
(Where X is one or more of Pd, Ir, Rh, and Ru), Pt—Mn—X ′ (where X ′ is Pd, Ir, Rh, Ru, Au, Ag) Or one or more of these elements).

In the case where the fixed magnetic layer is divided into the first fixed magnetic layer and the second fixed magnetic layer as in the present invention,
Even when the thickness of the antiferromagnetic layer is formed to be about half the thickness of the conventional antiferromagnetic layer, an exchange coupling magnetic field of 500 (Oe) or more can be obtained, and more preferably, 1000 (Oe).
The above exchange coupling magnetic field can be obtained.

Further, in the present invention, it is preferable that the free magnetic layer is formed so as to be divided into a first free magnetic layer and a second free magnetic layer via a nonmagnetic intermediate layer, similarly to the fixed magnetic layer. . An exchange coupling magnetic field (RKKY interaction) is generated between the first free magnetic layer and the second free magnetic layer, and the magnetization of the first free magnetic layer and the magnetization of the second free magnetic layer are changed. It is magnetized in an antiparallel state, and can be inverted with high sensitivity to an external magnetic field.

In the present invention, the film thickness ratio between the first free magnetic layer and the second free magnetic layer is formed within an appropriate range, and the first free magnetic layer and the second free magnetic layer are further formed. If the nonmagnetic intermediate layer interposed between the layers is formed of a Ru film or the like and the thickness of the nonmagnetic intermediate layer is formed within an appropriate range, an exchange coupling magnetic field of 500 (Oe) or more can be obtained. It is possible, and more preferably, an exchange coupling magnetic field of 1000 (Oe) or more can be obtained.

Further, according to the present invention, when an antiferromagnetic layer requiring heat treatment is used at the interface with the first fixed magnetic layer, the magnetic moment of the first fixed magnetic layer
Properly adjust the magnitude of the magnetic moment of the fixed magnetic layer,
Further, by appropriately adjusting the direction and magnitude of the magnetic field applied during the heat treatment, the magnetization of the first pinned magnetic layer can be directed in a desired direction, and the magnetization of the first pinned magnetic layer can be directed. And the magnetization of the second pinned magnetic layer can be appropriately controlled to be in an antiparallel state.

Further, according to the present invention, the direction of the sense current magnetic field formed by flowing the sense current
The first fixed magnetic layer and the second fixed magnetic layer are made to match the direction of the synthetic magnetic moment that can be obtained by adding the magnetic moment of the fixed magnetic layer and the magnetic moment of the second fixed magnetic layer. It is possible to further thermally stabilize the magnetization state with the magnetic layer.

The control of the sense current direction can be applied to any case where any antiferromagnetic material is used for the antiferromagnetic layer. For example, the antiferromagnetic layer and the fixed magnetic layer (the first fixed magnetic layer) may be used. Exchange coupling magnetic field (exchange anisotropic magnetic field) at the interface with
It does not matter whether a heat treatment is necessary or not in order to generate.

Further, even in the case of a single spin-valve thin film element in which the pinned magnetic layer is formed as a single layer as in the prior art, the direction of the sense current magnetic field formed by flowing the above-described sense current is also considered. By making the magnetization direction of the pinned magnetic layer coincide with that of the pinned magnetic layer, the magnetization of the pinned magnetic layer can be thermally stabilized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a spin-valve thin-film element according to a first embodiment of the present invention;

FIG. 2 is a cross-sectional view of the spin-valve thin film element shown in FIG. 1 as viewed from a surface facing a recording medium;

FIG. 3 is a cross-sectional view of a spin-valve thin-film element according to a second embodiment of the present invention;

FIG. 4 is a cross-sectional view of the spin-valve thin film element shown in FIG. 3 as viewed from a surface facing a recording medium;

FIG. 5 is a cross-sectional view of a spin-valve thin film element according to a third embodiment of the present invention;

FIG. 6 is a cross-sectional view of the spin-valve thin film element shown in FIG. 5, as viewed from a surface facing a recording medium;

FIG. 7 is a cross-sectional view of a spin-valve thin film element according to a fourth embodiment of the present invention;

FIG. 8 is a cross-sectional view of the spin-valve thin film element shown in FIG. 7, as viewed from a surface facing a recording medium.

FIG. 9 is a cross-sectional view of a spin-valve thin-film element according to a fifth embodiment of the present invention;

FIG. 10 is a cross-sectional view of the spin-valve thin film element shown in FIG. 9 as viewed from a surface facing a recording medium;

FIG. 11 is a cross-sectional view of a spin-valve thin film element according to a sixth embodiment of the present invention;

FIG. 12 is a cross-sectional view of the spin-valve thin film element shown in FIG. 11, as viewed from a surface facing a recording medium.

FIG. 13 is a cross-sectional view of a read head (reproducing head) viewed from a surface facing a recording medium.

FIG. 14 shows the relationship between the thickness of the second pinned magnetic layer (P2) and the exchange coupling magnetic field when the thickness of the first pinned magnetic layer (P1) is fixed at 20 or 40 Å;
And (the thickness of the first fixed magnetic layer (P1)) / (the thickness of the second fixed magnetic layer (P2)) and the exchange coupling magnetic field (Hex).
Graph showing the relationship with

FIG. 15 shows a relationship between the thickness of the second fixed magnetic layer (P2) and ΔMR (%) when the thickness of the first fixed magnetic layer (P1) is fixed at 20 or 40 Å. Graph,

FIG. 16 shows the relationship between the thickness of the first fixed magnetic layer (P1) and the exchange coupling magnetic field when the second fixed magnetic layer (P2) is fixed at 30 Å, and (first fixed magnetic layer). A graph showing the relationship between the thickness of the layer (P1) / (the thickness of the second pinned magnetic layer (P2)) and the exchange coupling magnetic field (Hex);

FIG. 17 is a graph showing the relationship between the thickness of the first fixed magnetic layer (P1) and ΔMR (%) when the second fixed magnetic layer (P2) is fixed at 30 Å;

FIG. 18 shows a dual spin-valve thin film element.
The relationship between the thickness of the first pinned magnetic layer (upper), the thickness of the first pinned magnetic layer (lower), and the exchange coupling magnetic field (Hex), and further, the film of the first pinned magnetic layer (upper P1) (Thickness) / (film thickness of second fixed magnetic layer (above P2)) and (film thickness of first fixed magnetic layer (below P1)) / (second fixed magnetic layer (P2
A graph showing the relationship between the thickness of the lower layer) and the exchange coupling magnetic field (Hex);

FIG. 19 is a graph showing the relationship between the thickness of Ru (nonmagnetic intermediate layer) interposed between the first pinned magnetic layer and the second pinned magnetic layer and the exchange coupling magnetic field (Hex);

FIG. 20 shows the use of four types of spin-valve thin film elements;
A graph showing the relationship between the PtMn (antiferromagnetic layer) film thickness and the exchange coupling magnetic field (Hex) of each spin valve thin film element;

FIG. 21 shows a PtMn of each dual spin-valve thin film element using two types of dual spin-valve thin film elements.
A graph showing the relationship between the thickness of the (antiferromagnetic layer) and the exchange coupling magnetic field (Hex);

FIG. 22 shows a PtMn of each dual spin-valve thin film element using two types of dual spin-valve thin film elements.
A graph showing the relationship between the thickness of the (antiferromagnetic layer) and ΔMR (%),

FIG. 23 shows the relationship between the thickness of the second free magnetic layer (F2) and the exchange coupling magnetic field (Hex) when the thickness of the first free magnetic layer (F1) is fixed at 50 Å, and No. 1 free magnetic layer (F1)) / (film thickness of second free magnetic layer (F2)) and exchange coupling magnetic field (Hex)
Graph showing the relationship with

FIG. 24 shows the relationship between the thickness of the first free magnetic layer (F1) and ΔMR (%) when the thickness of the second free magnetic layer (F2) is fixed at 20 Å, and A graph showing a relationship between the thickness of the free magnetic layer (F1) / (the thickness of the second free magnetic layer (F2)) and ΔMR (%);

FIG. 25 shows the relationship between the thickness of Ru (nonmagnetic intermediate layer) interposed between the first free magnetic layer (F1) and the second free magnetic layer (F2) and the exchange coupling magnetic field (Hex). Graph,

FIG. 26 shows a hysteresis loop in a spin-valve thin film element according to the present invention and a conventional spin-valve thin film element;

FIG. 27 shows a case where the antiferromagnetic layer is formed of PtMn,
A graph showing a relationship between an ambient temperature (° C.) and an exchange coupling magnetic field (Hex) in each of the spin-valve thin film elements formed of O and FeMn;

FIG. 28 is a cross-sectional view of a conventional spin-valve thin film element viewed from a surface facing a recording medium.

[Explanation of symbols]

10, 30, 50, 70, 91 Underlayer 11, 28, 31, 44, 51, 80, 92, 108
Antiferromagnetic layer 12, 27, 52, 79 First fixed magnetic layer 13, 26, 33, 42, 53, 59, 72, 78, 9
4, 100, 106 Non-magnetic intermediate layer 14, 25, 54, 77 Second pinned magnetic layer 15, 24, 35, 40, 55, 76, 96, 104
Nonmagnetic conductive layer 16, 21, 36 Free magnetic layer 19, 29, 45, 61, 81, 109 Protective layer 32, 93 First fixed magnetic layer (lower) 34, 95 Second fixed magnetic layer (lower) 41 , 105 Second fixed magnetic layer (upper) 43, 107 First fixed magnetic layer (upper) 56, 73, 101 First free magnetic layer 60, 71, 97 Second free magnetic layer 62, 82, 130 Hard bias layer 63, 83, 131 Conductive layer 112, 113, 114 Sense current

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] July 14, 1999 (1999.7.1)
4)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 4

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Claim 6

[Correction method] Change

[Correction contents]

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] Claim 11

[Correction method] Change

[Correction contents]

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] Claim 13

[Correction method] Change

[Correction contents]

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction contents]

According to the present invention, the spin-valve thin film element includes an antiferromagnetic layer, a first pinned magnetic layer, a nonmagnetic intermediate layer, a second pinned magnetic layer, a nonmagnetic conductive layer, and a free magnetic layer. A single spin-valve thin film element formed one by one, wherein, of the free magnetic layers divided into two layers, a free magnetic layer formed on a side in contact with a nonmagnetic conductive layer is used as a first free magnetic layer; Wherein the free magnetic layer is a second free magnetic layer, and the spin-valve thin-film element comprises:
A nonmagnetic conductive layer laminated above and below the free magnetic layer, and a second fixed magnetic layer / nonmagnetic layer laminated on one nonmagnetic conductive layer and below the other nonmagnetic conductive layer Dual spin valve type having three layers of an intermediate layer / first fixed magnetic layer and an antiferromagnetic layer laminated on one first fixed magnetic layer and below the other first fixed magnetic layer In the case where the free magnetic layer is a thin film element and one of the two free magnetic layers is a first free magnetic layer and the other free magnetic layer is a second free magnetic layer, (The thickness of the first free magnetic layer / the thickness of the second free magnetic layer)
It is preferably in the range of 0.56 to 0.83, or 1.25 to 5, and more preferably 0.61 to 0.
83, or 1.25 to 2.1.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction contents]

In the present invention, (the magnetic film thickness of the first fixed magnetic layer) / (the magnetic film thickness of the second fixed magnetic layer) is:
More preferably, it is in the range of 0.53 to 0.95, or 1.05 to 1.8. Further, in the present invention, the magnetic film thickness of the first fixed magnetic layer and the magnetic film thickness of the second fixed magnetic layer are both within the range of 10 to 70 (angstrom tesla), and | The magnetic film thickness of the fixed magnetic layer−the magnetic film thickness of the second fixed magnetic layer│ ≧ 2 (angstrom tesla). Further, in the present invention, the first magnetic film thickness of the magnetic film thickness and the second fixed magnetic layer of the fixed magnetic layer are both within the range of 10 to 50 (Å Tesla), and │ first Film thickness of fixed magnetic layer of second layer−magnetic film thickness of second fixed magnetic layer |
More preferably, ≧ 2 (Angstroms / Tesla).

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

In the present invention, the free magnetic layer may be divided into two layers via a non-magnetic intermediate layer. In the present invention, the spin-valve thin film element includes an antiferromagnetic layer, a first pinned magnetic layer, a non-magnetic intermediate layer, a second pinned magnetic layer, a non-magnetic conductive layer, and a free magnetic layer. A single spin-valve type thin film element, wherein a free magnetic layer formed on a side in contact with a nonmagnetic conductive layer among the two free magnetic layers is a first free magnetic layer, and the other free magnetic layer is When the layer is a second free magnetic layer, and the spin-valve thin film element is a non-magnetic conductive layer laminated on and around the free magnetic layer, and on one of the non-magnetic conductive layers A second pinned magnetic layer / non-magnetic intermediate layer laminated below the other non-magnetic conductive layer /
A dual spin-valve thin-film element having three first fixed magnetic layers and an antiferromagnetic layer laminated on one first fixed magnetic layer and under the other first fixed magnetic layer. When one of the two free magnetic layers is a first free magnetic layer and the other free magnetic layer is a second free magnetic layer, the first free magnetic layer is divided into two layers. (Magnetic film thickness of magnetic layer / magnetic film thickness of second free magnetic layer) is preferably in the range of 0.56 to 0.83 or 1.25 to 5, more preferably 0 to 5. .6
It is in the range of 1 to 0.83, or 1.25 to 2.1.

[Procedure amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0229

[Correction method] Change

[Correction contents]

In the spin valve type thin film element shown in FIG.
The second fixed magnetic layer 14 is formed below the nonmagnetic conductive layer 15. In this case, the first pinned magnetic layer 1
The direction of the sense current magnetic field is adjusted to the magnetization direction of the fixed magnetic layer having the larger magnetic moment of the second and second fixed magnetic layers 14 . As shown in FIG. 1, the magnetic moment of the second pinned magnetic layer 14 is larger than the magnetic moment of the first pinned magnetic layer 12 and the second pinned magnetic layer 1
The magnetic moment No. 4 is directed in a direction opposite to the illustrated Y direction (left direction in the drawing). Therefore, the first pinned magnetic layer 12
Is combined with the magnetic moment of the second pinned magnetic layer 14 to be directed in the opposite direction (left direction in the figure) to the Y direction in the figure.

[Procedure amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0230

[Correction method] Change

[Correction contents]

As described above, the nonmagnetic conductive layer 15 is formed above the second fixed magnetic layer 14 and the first fixed magnetic layer 12 . For this reason, the sense current magnetic field mainly generated by the sense current 112 flowing around the nonmagnetic conductive layer 15 is such that the sense current The flow direction of 112 may be controlled. By doing so, the direction of the combined magnetic moment of the first pinned magnetic layer 12 and the second pinned magnetic layer 14 matches the direction of the sense current magnetic field.

[Procedure amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0231

[Correction method] Change

[Correction contents]

As shown in FIG. 1, the sense current 112 flows in the X direction in the figure. According to the right-hand rule, a sense current magnetic field formed by flowing a sense current is formed clockwise with respect to the plane of the drawing. Therefore, a sense current magnetic field in the left direction in the drawing (opposite to the Y direction in the drawing) is applied to the layer below the nonmagnetic conductive layer 15, and the sense current magnetic field reinforces the synthetic magnetic moment. The exchange coupling magnetic field (RKKY interaction) acting between the first fixed magnetic layer 12 and the second fixed magnetic layer 14 is amplified, and the magnetization of the first fixed magnetic layer 12 and the second It is possible to more thermally stabilize the antiparallel state of magnetization of the fixed magnetic layer 14 .

[Procedure amendment 11]

[Document name to be amended] Statement

[Correction target item name] 0233

[Correction method] Change

[Correction contents]

In such an extremely high ambient temperature and when a large sense current flows, the magnetic moment of the first fixed magnetic layer 12 and the second fixed magnetic layer 1
4 is opposite to the direction of the sensed magnetic field, which can be obtained by adding the first fixed magnetic layer 12 to the second fixed magnetic layer 1.
The antiparallel state with the magnetization of No. 4 is easily broken.

[Procedure amendment 12]

[Document name to be amended] Statement

[Correction target item name] 0235

[Correction method] Change

[Correction contents]

The combined magnetic moment formed by the magnetic moment of the first fixed magnetic layer 12 and the magnetic moment of the second fixed magnetic layer 14 shown in FIG. 1 is directed rightward in the figure (Y direction in the figure). In this case, the sense current may be caused to flow in a direction opposite to the X direction in the drawing, so that the sense current magnetic field is formed counterclockwise with respect to the plane of the drawing.

Claims (30)

[Claims] An antiferromagnetic layer, a fixed magnetic layer formed in contact with the antiferromagnetic layer, and having a magnetization direction fixed by an exchange coupling magnetic field with the antiferromagnetic layer; A spin-valve thin-film element having a free magnetic layer formed with a magnetic conductive layer interposed in a direction crossing the magnetization direction of the fixed magnetic layer, wherein the fixed magnetic layer has a non-magnetic intermediate layer interposed therebetween. The fixed magnetic layer in contact with the antiferromagnetic layer is a first fixed magnetic layer, and the fixed magnetic layer in contact with the nonmagnetic conductive layer is a second fixed magnetic layer. (Film thickness of first pinned magnetic layer)
/ (Film thickness of second pinned magnetic layer) is 0.33 to 0.9
5. A spin-valve thin-film device, wherein the thickness is in the range of 1.0 or 1.05 to 4. 2. The ratio of (the thickness of the first fixed magnetic layer) / (the thickness of the second fixed magnetic layer) is in the range of 0.53 to 0.95, or 1.05 to 1.8. The spin-valve thin-film element according to claim 1, wherein 3. The thickness of the first fixed magnetic layer and the thickness of the second fixed magnetic layer are both within the range of 10 to 70 angstroms, and | the thickness of the first fixed magnetic layer. Second
2. The spin-valve thin-film element according to claim 1, wherein the thickness of the fixed magnetic layer is | ≧ 2 angstroms. 4. The film thickness of the first fixed magnetic layer and the film thickness of the second fixed magnetic layer are both within the range of 10 to 50 angstroms, and | the film thickness of the first fixed magnetic layer. Second
3. The spin-valve thin film element according to claim 2, wherein the thickness of the fixed magnetic layer is | ≧ 2 angstroms. 5. The spin-valve thin-film element according to claim 1, wherein said free magnetic layer is divided into two layers via a non-magnetic intermediate layer. 6. The spin-valve thin film element includes an antiferromagnetic layer, a first fixed magnetic layer, a nonmagnetic conductive layer, a second fixed magnetic layer, a nonmagnetic conductive layer, and a free magnetic layer formed one by one. A single spin-valve thin film element,
When the free magnetic layer formed on the side in contact with the nonmagnetic conductive layer among the divided free magnetic layers is the first free magnetic layer, and the other free magnetic layer is the second free magnetic layer, And the spin-valve thin film element, a non-magnetic conductive layer stacked on top of the free magnetic layer,
A second pinned magnetic layer / non-magnetic intermediate layer / first layer laminated on one of the non-magnetic conductive layers and under the other non-magnetic conductive layer.
A dual spin-valve thin-film element having three fixed magnetic layers, and an antiferromagnetic layer laminated on one first fixed magnetic layer and below the other first fixed magnetic layer; When one of the two free magnetic layers is a first free magnetic layer and the other free magnetic layer is a second free magnetic layer, the first free magnetic layer is divided into two layers. Thickness / the thickness of the second free magnetic layer) is from 0.56 to
The spin-valve thin-film element according to claim 5, wherein the thickness is in the range of 0.83 or 1.25 to 5. 7. The method according to claim 7, wherein (thickness of first free magnetic layer / second thickness of second free magnetic layer).
7. The spin-valve thin-film element according to claim 6, wherein the thickness of the free magnetic layer is in the range of 0.61 to 0.83 or 1.25 to 2.1. 8. An antiferromagnetic layer, a fixed magnetic layer formed in contact with the antiferromagnetic layer, and having a magnetization direction fixed by an exchange coupling magnetic field with the antiferromagnetic layer by heat treatment in a magnetic field; Formed on the fixed magnetic layer via the non-magnetic conductive layer,
In a spin-valve thin film element having a free magnetic layer whose magnetization is aligned in a direction crossing the magnetization direction of the fixed magnetic layer, the fixed magnetic layer may be connected to a nonmagnetic intermediate layer through a nonmagnetic intermediate layer.
The fixed magnetic layer in contact with the antiferromagnetic layer is a first fixed magnetic layer, the fixed magnetic layer in contact with the nonmagnetic conductive layer is a second fixed magnetic layer, and the saturation magnetization M
When the product of s and film thickness t is a magnetic film thickness (magnetic moment), (magnetic film thickness of first fixed magnetic layer) / (second film thickness)
Magnetic thickness of the fixed magnetic layer) is 0.33 to 0.95,
Alternatively, the spin-valve thin film element is in the range of 1.05 to 4. 9. The magnetic layer thickness of the first pinned magnetic layer
/ (Magnetic thickness of the second pinned magnetic layer) is 0.53 to
The spin-valve thin-film element according to claim 8, wherein the thickness is in the range of 0.95 or 1.05 to 1.8. 10. The magnetic thickness of the first fixed magnetic layer and the magnetic thickness of the second fixed magnetic layer are both 10 to 70.
(Angstrom Tesla) and |
9. The spin-valve thin-film element according to claim 8, wherein the magnetic film thickness of the first fixed magnetic layer−the magnetic film thickness of the second fixed magnetic layer│ ≧ 2 (angstroms / tesla). 11. The film thickness of the first fixed magnetic layer and the second fixed magnetic layer.
Are in the range of 10 to 50 (Angstroms / Tesla), and | the magnetic film thickness of the first fixed magnetic layer−the magnetic film thickness of the second fixed magnetic layer | ≧ 2
10. The spin-valve thin film element according to claim 9, which is (Angstroms Tesla). 12. The spin-valve thin-film element according to claim 8, wherein the free magnetic layer is divided into two layers via a non-magnetic intermediate layer. 13. The spin-valve thin film element according to claim 1, wherein an antiferromagnetic layer, a first fixed magnetic layer, a nonmagnetic conductive layer, a second fixed magnetic layer, a nonmagnetic conductive layer, and a free magnetic layer are formed one by one. A single spin-valve thin film element, wherein the free magnetic layer formed on the side in contact with the non-magnetic conductive layer is the first free magnetic layer, and the other free magnetic layer is divided into the two free magnetic layers. When the magnetic layer is a second free magnetic layer, and the spin-valve thin film element includes a nonmagnetic conductive layer stacked on and under the free magnetic layer and one of the nonmagnetic conductive layers. And a second pinned magnetic layer / non-magnetic intermediate layer /
A dual spin-valve thin-film element having three first fixed magnetic layers and an antiferromagnetic layer laminated on one first fixed magnetic layer and below the other first fixed magnetic layer. When one of the two free magnetic layers is a first free magnetic layer and the other free magnetic layer is a second free magnetic layer, the first free magnetic layer is divided into two free magnetic layers. 13. The spin-valve thin film according to claim 12, wherein (magnetic thickness of magnetic layer / magnetic thickness of second free magnetic layer) is in the range of 0.56 to 0.83, or 1.25 to 5. element. 14. The method according to claim 1, wherein (the magnetic film thickness of the first free magnetic layer / the magnetic film thickness of the second free magnetic layer) is 0.61 to 0.61.
The spin-valve thin-film element according to claim 13, wherein the thickness is in the range of 0.83 or 1.25 to 2.1. 15. The non-magnetic intermediate layer interposed between the first pinned magnetic layer and the second pinned magnetic layer is made of Ru, Rh, Ir,
The spin-valve thin-film element according to claim 1, wherein the spin-valve thin-film element is formed of one or more alloys of Cr, Re, and Cu. 16. The spin-valve thin film element has an antiferromagnetic layer below the free magnetic layer, a first pinned magnetic layer formed in contact with the antiferromagnetic layer, and a nonmagnetic layer. 16. The non-magnetic intermediate layer interposed between the conductive layer and the second pinned magnetic layer formed in contact with the conductive layer has a thickness in a range of 3.6 to 9.6 angstroms. The spin-valve thin film element according to any one of the above. 17. The film thickness of the non-magnetic intermediate layer is from 4.0 to 4.0.
17. The spin-valve thin-film device according to claim 16, wherein the thickness is in the range of 9.4 angstroms. 18. A first fixed magnetic layer formed in contact with an antiferromagnetic layer having an antiferromagnetic layer above a free magnetic layer, and a first fixed magnetic layer formed in contact with a nonmagnetic conductive layer. The thickness of the non-magnetic intermediate layer interposed between the second fixed magnetic layer and the second fixed magnetic layer is 2.5
~ 6.4 angstroms, or 6.6 ~ 10.7
The spin-valve thin-film element according to claim 1, wherein the spin-valve thin-film element is in the range of Å. 19. The film thickness of the non-magnetic intermediate layer is from 2.8 to
19. The spin-valve thin film element according to claim 18, wherein the thickness is in the range of 6.2 angstrom or 6.8 to 10.3 angstrom. 20. The spin-valve thin film element according to claim 1, wherein said antiferromagnetic layer is formed of a PtMn alloy. 21. The antiferromagnetic layer is made of X—Mn (where X is any one of Pd, Ir, Rh, and Ru or 2
20. The spin-valve thin-film element according to claim 1, wherein the spin-valve thin-film element is made of at least one element. 22. The antiferromagnetic layer is made of Pt—Mn—X ′.
(Where X 'is Pd, Ir, Rh, Ru, Au, Ag
20. The spin-valve thin-film element according to claim 1, wherein the spin-valve thin-film element is formed of any one or more of the following elements: 23. The spin-valve type thin film element comprises an antiferromagnetic layer, a first pinned magnetic layer, a non-magnetic intermediate layer, a second pinned magnetic layer, a non-magnetic conductive layer, and a free magnetic layer. 23. The spin valve thin film element according to claim 1, wherein the formed single spin valve thin film element has a film thickness of the antiferromagnetic layer in a range of 90 to 200 angstroms. 24. The antiferromagnetic layer has a thickness of 100 to 2
24. The spin-valve thin-film device according to claim 23, wherein the thickness is in the range of 00 Å. 25. The spin-valve thin-film element, wherein a nonmagnetic conductive layer laminated above and below a free magnetic layer, and one above the nonmagnetic conductive layer and below the other nonmagnetic conductive layer Three layers of a second pinned magnetic layer / a non-magnetic intermediate layer / a first pinned magnetic layer, and a layer stacked on one first pinned magnetic layer and under the other first pinned magnetic layer. 23. A dual spin-valve thin film element having an antiferromagnetic layer formed thereon, wherein the thickness of the antiferromagnetic layer is in the range of 100 to 200 angstroms. Spin valve type thin film element. 26. The antiferromagnetic layer has a thickness of 110 to 2
26. The spin-valve thin-film element according to claim 25, wherein the thickness is within the range of 00 angstrom. 27. A non-magnetic intermediate layer interposed between the first free magnetic layer and the second free magnetic layer, wherein Ru, Rh, I
13. The spin-valve thin-film element according to claim 5, wherein the spin-valve thin-film element is formed of one or more alloys of r, Cr, Re, and Cu. 28. The nonmagnetic intermediate layer has a thickness of 5.5 to 5.5.
28. The spin-valve thin-film device according to claim 27, wherein the thickness is in the range of 10.0 angstroms. 29. The film thickness of the nonmagnetic intermediate layer is from 5.9 to 5.9.
29. The spin-valve thin film device according to claim 28, wherein the thickness is in the range of 9.4 angstroms. 30. A thin-film magnetic head, wherein a shield layer is formed above and below the spin-valve thin-film element according to claim 1 via a gap layer.