JP2003045010A - Magneto-resistance effect device, its manufacturing method, thin-film magnetic head and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the sensitivity, the output and the output stability of a magneto-resistance effect device, and to accurately decide an effective reading track width. SOLUTION: The magneto-resistance effect device is provided with an MR element 5, a bias magnetic field application layer 18 arranged to be adjacent to each side of the MR element 5, and tow electrode layers 6 for supplying sense currents to the MR element 5. The electrode layers 6 are arranged to overlap each other in one surface of the MR element 5. The total overlapping amount of the two electrode layers 6 is less than 0.3 μm. The MR element 5 has a substrate layer, a free layer, a spacer layer, a pind layer, an aitiferromagnetic layer and a gap layer, which are laminated from the lower aide in this order. The free layer includes a first soft magnetic layer, a middle layer and a second soft magnetic layer. The middle layer limits the path of the movement of electrons at least partially reflected when the sense current flows through the MR element 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive effect device having a magnetoresistive effect element and a manufacturing method thereof, and a thin film magnetic head having a magnetoresistive effect element and a manufacturing method thereof.

[0002]

2. Description of the Related Art In recent years, as the areal recording density of hard disk devices has increased, there has been a demand for improved performance of thin film magnetic heads. The thin film magnetic head has a structure in which a read head having a magnetoresistive effect element for reading (hereinafter also referred to as an MR (Magneto-resistive) element) and a recording head having an inductive electromagnetic conversion element for writing are stacked. Composite thin film magnetic heads are widely used.

As an MR element, an anisotropic magnetoresistive (Anis
AMR element using the tropic magneto-resistive effect, GMR element using the giant magnetoresistive effect, and tunneling magneto-resistance (Tunnel-type)
There is a TMR element using the magnetoresistive effect.

The reproducing head is required to have high sensitivity and high output. As a reproducing head satisfying this requirement, a GMR head using a spin valve type GMR element has already been mass-produced.

Further, the reproducing head is required to have a small Barkhausen noise. Barkhausen noise is noise generated due to the movement of the domain wall of the magnetic domain in the MR element. When this Barkhausen noise occurs, the output changes abruptly, resulting in a decrease in the signal-to-noise ratio (SN ratio) and an increase in the error rate.

As a means for reducing Barkhausen noise, a bias magnetic field (hereinafter also referred to as a longitudinal bias magnetic field) is applied to the MR element in the longitudinal direction. The longitudinal bias magnetic field applied to the MR element is
For example, it is carried out by disposing a permanent magnet or a bias magnetic field applying layer composed of a laminated body of a ferromagnetic layer and an antiferromagnetic layer on both sides of the MR element.

In the reproducing head having a structure in which the bias magnetic field applying layers are arranged on both sides of the MR element, the two electrode layers for supplying a current for signal detection (hereinafter referred to as a sense current) to the MR element have a bias magnetic field. It is arranged so as to be in contact with the application layer.

By the way, for example, Japanese Patent Laid-Open No. 11-31313.
As described in the publication, when the bias magnetic field applying layers are arranged on both sides of the MR element, the direction of magnetization is changed by the magnetic field from the bias magnetic field applying layer in the vicinity of the end portion of the MR element adjacent to the bias magnetic field applying layer. It is known that a region where the signal magnetic field is fixed and cannot be sensed (hereinafter referred to as a dead region) occurs.

Therefore, when the electrode layer is arranged so as not to overlap the MR element, there is a problem that the output of the reproducing head is lowered because the sense current passes through the dead region.

In order to solve this problem, Japanese Patent Laid-Open No. 8-4
As shown in JP-A-5037, JP-A-9-2821818, JP-A-11-31313, and JP-A-2000-76629, the electrode layer partially overlaps the MR element (hereinafter, referred to as overlapping). It is being arranged as.

Here, the length of the region where one electrode layer overlaps with the MR element, that is, the distance between one end of the one electrode layer and one end of the corresponding MR element (hereinafter referred to as "overlap amount"). Pay attention to). JP-A-8
-45037 gazette does not particularly describe the range of the overlap amount. The range of the overlap amount described in JP-A-9-2821818 is 0.25 to 2
It is μm. The range of the overlap amount described in JP-A-11-31313 is 0.15 to 0.5 μ.
It has become m. Moreover, the range of the overlap amount described in Japanese Patent Laid-Open No. 2000-76629 is 0.15.
It is about 5 μm.

[0012]

As described above, the reproducing head has the structure in which the bias magnetic field applying layers are arranged on both sides of the MR element and the electrode layers are arranged so as to overlap with the MR element (hereinafter referred to as the electrode layer). It is possible to reduce Barkhausen noise while preventing the output of the reproducing head from being lowered by adopting the overlap structure).

However, according to the research by the present inventor, in the reproducing head having the electrode layer overlapping structure, the distance between the two electrode layers, that is, the optical magnetic read track width and the effective magnetic read track width are different. I found out. Further, in the range of the overlap amount described in each of the above publications, the difference between the optical magnetic read track width and the effective magnetic read track width, and the variation of the effective magnetic read track width. It was found that there was a problem in terms of reproducing head characteristics and yield.

In Japanese Patent Laid-Open No. 2000-187813, the width L2 of the magnetic sensitive portion of the spin valve film and the length L of the portion where the permanent magnet film and the electrode film overlap the magnetic sensitive portion.
A technique of setting the ratio L1 / L2 of 1 to 0 to 10% is disclosed. This technique aims to prevent the generation of noise due to the permanent magnet film overlapping the spin valve film. The publication discloses a structure in which only the permanent magnet film overlaps the magnetic sensing part and a structure in which both the permanent magnet film and the electrode film overlap the magnetic sensing part. No structure is disclosed in which the magnet films do not overlap and only the electrode films overlap.

The present invention has been made in view of the above problems, and an object thereof is to improve sensitivity, output and output stability, and to effectively determine an effective read track width, and a magnetoresistive device. It is to provide a thin film magnetic head and a manufacturing method thereof.

[0016]

A magnetoresistive device or a thin film magnetic head according to the present invention has a magnetoresistive element having two surfaces facing each other and two side portions respectively connecting the two surfaces. And two bias magnetic field applying layers which are arranged so as to be adjacent to each side portion of the magnetoresistive effect element and apply a bias magnetic field to the magnetoresistive effect element, and which are respectively adjacent to one surface of each bias magnetic field applying layer. And two electrode layers for passing a current for signal detection to the magnetoresistive effect element, and at least one of the two electrode layers is partially disposed on one surface of the magnetoresistive effect element. The total length of the regions where the electrode layers overlap with one surface of the magnetoresistive effect element is less than 0.3 μm, and the magnetoresistive effect element has two surfaces facing each other. Non-magnetic A soft magnetic layer disposed adjacent to one surface of the non-magnetic layer, a pinned layer disposed adjacent to the other surface of the non-magnetic layer and having a fixed magnetization direction, and a pinned layer. Of the antiferromagnetic layer, which is arranged so as to be adjacent to the surface opposite to the non-magnetic layer, fixes the direction of magnetization in the pinned layer, and at least a part of the current for signal detection flows through the magnetoresistive element. And a layer for restricting the path of movement of the electrons by reflecting the electrons.

In the magnetoresistive device or thin film magnetic head of the present invention, a bias magnetic field applying layer is provided so as to be adjacent to each side of the magnetoresistive element, and at least one of the two electrode layers is provided with the magnetoresistive effect. By arranging the element so as to partially overlap with one surface thereof, the sensitivity, output and output stability of the magnetoresistive device or the thin film magnetic head are improved. Furthermore, in the present invention, the effective read track width can be accurately determined by setting the total length of the region where the electrode layer overlaps one surface of the magnetoresistive effect element to less than 0.3 μm. Furthermore, in the present invention, since the magnetoresistive effect element has the layer that restricts the path through which electrons move, the resistance change rate of the magnetoresistive effect element can be increased.

In the magnetoresistive device or the thin-film magnetic head of the present invention, the soft magnetic layer includes two layers, and the layer that restricts the electron moving path may be provided between the two layers. .

Further, in the magnetoresistive device or the thin film magnetic head of the present invention, the pinned layer includes two layers, and the layer for restricting the path of electron movement may be provided between the two layers. Good.

Further, in the magnetoresistive device or the thin film magnetic head of the present invention, the two electrode layers are both arranged so as to partially overlap with one surface of the magnetoresistive element, and each electrode layer is formed in the magnetoresistive element. The lengths of the regions overlapping the one surface may be less than 0.15 μm.

In the magnetoresistive device or thin film magnetic head of the present invention, the distance between the two electrode layers is 0.6 μm.
It may be m or less.

The method of manufacturing a magnetoresistive device according to the present invention comprises:
A magnetoresistive effect element having two surfaces facing each other and two side portions respectively connecting the two surfaces, and a magnetoresistive effect element arranged so as to be adjacent to each side portion of the magnetoresistive effect element. And two bias magnetic field applying layers for applying a bias magnetic field to the magnetoresistive effect element and two bias magnetic field applying layers which are arranged so as to be adjacent to one surface of each bias magnetic field applying layer. A method of manufacturing a magnetoresistive device including an electrode layer.

According to the method of manufacturing a thin film magnetic head of the present invention, each of the magnetoresistive effect element and the magnetoresistive effect element having two surfaces facing each other and two side portions connecting the two surfaces, respectively. Two bias magnetic field applying layers that are arranged so as to be adjacent to the side portions and apply a bias magnetic field to the magnetoresistive effect element, and are arranged so as to be adjacent to one surface of each bias magnetic field applying layer, respectively. It is a method of manufacturing a thin film magnetic head including two electrode layers for flowing a current for signal detection to an effect element.

A method of manufacturing a magnetoresistive device or a method of manufacturing a thin film magnetic head according to the present invention comprises a step of forming a magnetoresistive element, a step of forming a bias magnetic field applying layer,
And a step of forming an electrode layer, at least one of the two electrode layers is arranged so as to partially overlap with one surface of the magnetoresistive effect element, and the electrode layer has one surface of the magnetoresistive effect element. The total length of the regions overlapping with each other is less than 0.3 μm, and the magnetoresistive effect element is arranged so as to be adjacent to the nonmagnetic layer having two surfaces facing each other and one surface of the nonmagnetic layer. The pinned layer, which is arranged so as to be adjacent to the other surface of the soft magnetic layer and the non-magnetic layer and has a fixed magnetization direction, and is adjacent to the surface of the pinned layer opposite to the non-magnetic layer. An antiferromagnetic layer that is arranged and fixes the direction of magnetization in the pinned layer, and a layer that reflects at least part of the electrons when the current for signal detection flows through the magnetoresistive element and limits the path through which the electrons move. And have.

In the method of manufacturing the magnetoresistive device or the method of manufacturing the thin film magnetic head of the present invention, the bias magnetic field applying layer is provided so as to be adjacent to each side of the magnetoresistive element.
By arranging at least one of the two electrode layers so as to partially overlap with one surface of the magnetoresistive effect element, the sensitivity, output and output stability of the magnetoresistive effect device or the thin film magnetic head are improved. Furthermore, in the present invention, the effective read track width can be accurately determined by setting the total length of the region where the electrode layer overlaps one surface of the magnetoresistive effect element to less than 0.3 μm. Furthermore, in the present invention, since the magnetoresistive effect element has the layer that restricts the path through which electrons move, the resistance change rate of the magnetoresistive effect element can be increased. In the method of manufacturing a magnetoresistive device or the method of manufacturing a thin-film magnetic head of the present invention, the soft magnetic layer includes two layers, and the layer that restricts the electron movement path is provided between the two layers. May be.

Further, in the method of manufacturing the magnetoresistive device or the method of manufacturing the thin film magnetic head of the present invention, the pinned layer includes two layers, and the layer that restricts the electron movement path is between the two layers. May be provided.

Further, in the method of manufacturing the magnetoresistive device or the method of manufacturing the thin film magnetic head of the present invention, the two electrode layers are arranged so as to partially overlap with one surface of the magnetoresistive element, and each of the electrodes is formed. The lengths of the regions where the layers overlap with one surface of the magnetoresistive effect element may be both less than 0.15 μm.

In the method of manufacturing the magnetoresistive device or the method of manufacturing the thin film magnetic head of the present invention, the distance between the two electrode layers may be 0.6 μm or less.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. [First Embodiment] First, an outline of a thin film magnetic head and a method of manufacturing the same according to a first embodiment of the present invention will be described with reference to FIGS. Note that FIG.
6 to 6, (a) shows a cross section perpendicular to the air bearing surface, and (b) shows a cross section parallel to the air bearing surface of the magnetic pole portion.

In the method of manufacturing the thin film magnetic head according to the present embodiment, first, as shown in FIG. 3, a sputtering method is performed on a substrate 1 made of a ceramic material such as AlTiC (Al ₂ O ₃ .TiC). Alumina (Al
_An insulating layer 2 made of an insulating material such as ₂ O ₃ ) or silicon dioxide (SiO ₂ ) is formed to have a thickness of 1 to 20 μm, for example.
Next, a lower shield layer 3 for a reproducing head made of a magnetic material is formed on the insulating layer 2 to have a thickness of, for example, 0.1 to 5 μm. The magnetic material used for the lower shield layer 3 is Fe.
AiSi, NiFe, CoFe, CoFeNi, Fe
N, FeZrN, FeTaN, CoZrNb, CoZr
Ta and the like. The lower shield layer 3 is formed by a sputtering method, a plating method, or the like.

Next, a lower shield gap film 4 made of an insulating material such as Al ₂ O ₃ or SiO ₂ is formed on the lower shield layer 3 by a sputtering method or the like, for example, 10 to 200 n.
It is formed to a thickness of m. Next, the lower shield gap film 4
An MR element (magnetoresistive effect element) 5 for reproduction is formed thereon with a thickness of, for example, several tens of nm by a sputtering method or the like. Next, although not shown, two bias magnetic fields are applied by a sputtering method or the like to apply a longitudinal bias magnetic field to the MR element 5 so as to be adjacent to each side of the MR element 5 on the lower shield gap film 4. Form the layers. Next, on the lower shield gap film 4 and the bias magnetic field applying layer, a pair of electrode layers 6 electrically connected to the MR element 5 are formed with a thickness of several tens nm by a sputtering method or the like. Next, on the lower shield gap film 4 and the MR element 5, Al ₂ O ₃ and SiO ₂ are formed by a sputtering method or the like.
The upper shield gap film 7 made of an insulating material such as is formed to a thickness of, for example, 10 to 200 nm.

Each layer constituting the reproducing head is patterned by a general etching method using a resist pattern, a lift-off method or a method using these in combination.

Next, on the upper shield gap film 7,
An upper shield layer / lower pole layer (hereinafter, referred to as an upper shield layer) 8 made of a magnetic material and used for both a reproducing head and a recording head is formed to a thickness of 0.5 to 4.0 μm, for example. The magnetic material used for the upper shield layer 8 is a soft magnetic material such as NiFe, CoFe, CoFeNi, and FeN. The upper shield layer 8 is formed by a sputtering method, a plating method, or the like.

Next, a recording gap layer 9 made of an insulating material such as Al ₂ O ₃ or SiO ₂ is formed on the upper shield layer 8 by a sputtering method or the like to have a thickness of 10 to 500 nm, for example. Next, in order to form a magnetic path, the recording gap layer 9 is partially etched to form a contact hole 9a in the central portion of a thin film coil described later.

Next, an insulating layer 10 made of, for example, a thermosetting photoresist is formed on the recording gap layer 9 at the portion where the thin film coil is to be formed. Next, the first layer portion 11 of the thin film coil made of a conductive material such as Cu is formed on the insulating layer 10 by frame plating or the like. Next, the insulating layer 10 and the first layer portion 1 of the thin-film coil
An insulating layer 12 made of, for example, a thermosetting photoresist is formed so as to cover 1. Next, the second layer portion 13 of the thin-film coil made of a conductive material such as Cu is formed on the insulating layer 12 by frame plating or the like. Next, an insulating layer 14 made of, for example, thermosetting photoresist is formed so as to cover the insulating layer 12 and the second layer portion 13 of the thin-film coil. The first layer portion 11 and the second layer portion 13 of the thin-film coil are connected to each other and wound around the contact hole 9a. The combined thickness of the first layer portion 11 and the second layer portion 13 is, for example, 2 to 5 μm, and the combined thickness of the insulating layers 10, 12, and 14 is, for example, 3
˜20 μm.

Next, as shown in FIG. 4, from the air bearing surface (medium facing surface) 30 to the contact holes 9a through the insulating layers 12 and 14, the upper magnetic pole layer for a recording head made of a magnetic material. 15 is formed to a thickness of 3 to 5 μm, for example. The magnetic material used for the top pole layer 15 is a soft magnetic material such as NiFe, CoFe, CoFeNi, and FeN.

Of the lower magnetic pole layer (upper shield layer 8) and the upper magnetic pole layer 15, portions of the lower magnetic pole layer (upper shield layer 8) facing each other with the recording gap layer 9 on the air bearing surface 30 side are respectively the lower magnetic pole layer (upper shield layer 8). The magnetic pole portion and the magnetic pole portion of the upper magnetic pole layer 15. In this embodiment,
The magnetic pole portion of the upper magnetic pole layer 15 has a width equal to the recording track width and defines the recording track width. The lower magnetic pole layer (upper shield layer 8) and the upper magnetic pole layer 15 are magnetically coupled to each other through the contact hole 9a.

Next, as shown in FIG. 5, the top pole layer 1
The recording gap layer 9 is selectively etched by dry etching using the magnetic pole portion 5 as a mask. In this dry etching, for example, BCl ₂ , Cl _{2 is used.}
Reactive ion etching (RIE) using a gas such as chlorine-based gas such as CF ₄ or SF ₆ or fluorine-based gas such as SF ₆ is used. Next, the upper shield layer 8 is selectively etched, for example, by 0.3 to 0.6 by, for example, argon ion milling.
Etching is performed by about μm to obtain a trim structure as shown in FIG. With this trim structure, it is possible to prevent an effective increase in the track width due to the spread of the magnetic flux generated when writing a narrow track.

Next, as shown in FIG. 6, by sputtering or the like, the whole, the Al ₂ O _3, a protective layer 16 made of an insulating material such as SiO _2, for example, is formed on the 5~50μm thickness The surface is flattened, and an electrode pad (not shown) is formed thereon. Finally, the slider including each of the above layers is polished to form the air bearing surfaces 30 of the recording head and the reproducing head, and the thin film magnetic head according to the present embodiment is completed.

The thin-film magnetic head according to the present embodiment manufactured in this manner has a medium facing surface (air bearing surface 30) facing the recording medium, a reproducing head and a recording head. The reproducing head includes an MR element 5, a lower shield layer 3 and an upper shield layer 8 for shielding the MR element 5, which are arranged so that a part of the air bearing surface 30 side faces the MR element 5. have.
The reproducing head is also the magnetoresistive device according to this embodiment.

The recording heads are magnetically coupled to each other,
A lower magnetic pole layer (upper shield layer 8) and an upper magnetic pole layer 15 including magnetic pole portions facing each other on the air bearing surface 30 side and each including at least one layer, and a magnetic pole portion of the lower magnetic pole layer (upper shield layer 8). And the recording gap layer 9 provided between the upper magnetic pole layer 15 and the magnetic pole portion of the upper magnetic pole layer 15.
And at least part of the lower magnetic pole layer (upper shield layer 8)
And the thin film coils 11 and 13 disposed between the upper magnetic pole layer 15 and the upper magnetic pole layer 15 while being insulated from them. The magnetic pole portion of the upper magnetic pole layer 15 defines the recording track width.

Next, with reference to FIG. 1, the structure of the reproducing head according to the present embodiment, that is, the structure of the magnetoresistive device according to the present embodiment, and the manufacturing method thereof will be described in detail. FIG. 1 is a sectional view showing a section parallel to the air bearing surface of the magnetoresistive effect device according to the present embodiment.

As shown in FIG. 1, the magnetoresistive device according to the present embodiment has two surfaces facing each other.
MR having two sides each connecting two faces
The element 5, two bias magnetic field applying layers 18 arranged adjacent to each side of the MR element 5 and applying a longitudinal bias magnetic field to the MR element 5, and one of the bias magnetic field applying layers 18 respectively. Placed adjacent to the face of
The MR element 5 is provided with two electrode layers 6 for flowing a sense current which is a current for signal detection. In FIG. 1, the electrode layer 6 is arranged on the bias magnetic field applying layer 18, but in the region where the bias magnetic field applying layer 18 is not present, the electrode layer 6 is formed.
Are arranged on the lower shield gap film 4. The magnetoresistive device is covered with the lower shield gap film 4 and the upper shield gap film 7.

The method of manufacturing the magnetoresistive device includes a step of forming the MR element 5 on the lower shield gap film 4,
A bias magnetic field applying layer 1 is formed on the lower shield gap film 4.
8 and a step of forming the electrode layer 6 on the lower shield gap film 4 and the bias magnetic field applying layer 18.

In the present embodiment, at least one of the two electrode layers 6 is arranged so as to partially overlap with one surface of the MR element 5 (hereinafter referred to as “overlap”). The total length of the regions where the two electrode layers 6 overlap one surface of the MR element 5 is less than 0.3 μm. The length of the region where one electrode layer 6 overlaps with one surface of the MR element 5 (hereinafter referred to as the amount of overlap) is equal to the end of the one electrode layer 6 and the MR element 5 corresponding thereto. The distance from one end of the. Also,
In the present embodiment, the two bias magnetic field applying layers 18 are
Neither overlaps one surface of the MR element 5.

FIG. 2 is a perspective view showing the structure of layers of the MR element 5 in the present embodiment. M in the present embodiment
The R element 5 is a spin valve GMR element.
The MR element 5 is composed of an underlayer 21 and a soft magnetic layer which are sequentially stacked from the lower shield gap film 4 side, a free layer 22 in which the direction of magnetization changes according to a signal magnetic field from a recording medium, and a nonmagnetic conductive layer. It has a spacer layer 23 composed of layers, a pinned layer 24 whose magnetization direction is fixed, an antiferromagnetic layer 25 which fixes the magnetization direction in the pinned layer 24, and a cap layer 26. The MR element 5 is manufactured by sequentially stacking the above layers from the lower shield gap film 4 side.

As described above, the MR element 5 has a spacer layer (nonmagnetic layer) 23 having two surfaces facing opposite sides,
The free layer (soft magnetic layer) 22 arranged so as to be adjacent to one surface (lower surface) of the spacer layer 23 and the other surface (upper surface) of the spacer layer 23 are arranged so as to have a magnetization direction. A pinned layer 24 having a fixed pin, and this pinned layer 2
4 has an antiferromagnetic layer 25 which is arranged so as to be adjacent to the surface opposite to the spacer layer 23 and fixes the magnetization direction of the pinned layer 24.

In this embodiment, the pinned layer 24 includes a nonmagnetic spacer layer 24b and two ferromagnetic layers 24a and 24c arranged so as to sandwich the nonmagnetic spacer layer 24b. The pinned layer 24 is formed by stacking a ferromagnetic layer 24a, a nonmagnetic spacer layer 24b, and a ferromagnetic layer 24c in this order from the spacer layer 23 side. The two ferromagnetic layers 24a and 24c are antiferromagnetically coupled, and their magnetization directions are fixed in opposite directions.

The underlayer 21 has a thickness of 4 to 6 nm, for example. Examples of the material of the base layer 21 include Ta and NiC.
r is used.

The thickness of the free layer 22 is, for example, 3 to 8 nm.
Is. In the present embodiment, the free layer 22 includes two soft magnetic layers. Of these two soft magnetic layers, the layer on the side of the underlayer 21 is called the first soft magnetic layer, and the spacer layer 23
The layer on the side is called the second soft magnetic layer.

The thickness of the first soft magnetic layer is, for example, 1 to 8 n.
m. The first soft magnetic layer is made of, for example, Ni, Co, F
It is made of a magnetic material containing at least Ni in the group consisting of e, Ta, Cr, Rh, Mo and Nb. Specifically, the first soft magnetic layer is formed of [Ni _x Co _y Fe
_{100- (x + y)} ] _100-Z M _IZ . In the formula, M _I is Ta, Cr, Rh, Mo and Nb.
Of these, at least one is represented, and x, y, and z are in the range of 75 ≦ x ≦ 90, 0 ≦ y ≦ 15, and 0 ≦ z ≦ 15 in atomic%, respectively.

The thickness of the second soft magnetic layer is, for example, 0.5 to
It is 3 nm. The second soft magnetic layer is made of, for example, Ni or Co.
And a magnetic material containing at least Co in the group consisting of Fe and Fe. Specifically, the second soft magnetic layer has a Co _x whose (111) plane is oriented in the stacking direction.
It is preferably composed of Fe _y Ni _{100- (x + y)} .
In the formula, x and y are 70% x% 100 and 0, respectively, in atomic%.
It is within the range of ≦ y ≦ 25.

The spacer layer 23 has a thickness of, for example, 1.8 to
It is 3.0 nm. The spacer layer 23 is, for example, Cu,
At least one selected from the group consisting of Au and Ag is 80
It is composed of a non-magnetic conductive material containing at least wt%.

Ferromagnetic layers 24a and 24c of the pinned layer 24
Is made of, for example, a ferromagnetic material containing at least Co in the group consisting of Co and Fe. In particular, the (111) plane of this magnetic material is preferably oriented in the stacking direction. The total thickness of the ferromagnetic layers 24a and 24c is, for example, 3 to 4.5 nm.

The thickness of the nonmagnetic spacer layer 24b is, for example, 0.2 to 1.2 nm. Non-magnetic spacer layer 24b
Is made of, for example, a non-magnetic material containing at least one selected from the group consisting of Ru, Rh, Re, Cr and Zr. The nonmagnetic spacer layer 24b causes antiferromagnetic exchange coupling between the ferromagnetic layers 24a and 24c, and fixes the magnetizations of the ferromagnetic layer 24a and the ferromagnetic layer 24c in opposite directions. It is for doing. In addition,
The magnetization of the ferromagnetic layer 24a and the magnetization of the ferromagnetic layer 24c are opposite to each other, which means that the directions of these two magnetizations are 1 with respect to each other.
Not only when they differ by 80 °, but the two magnetization directions are 18
Including the case of 0 ° ± 20 ° difference.

The thickness of the antiferromagnetic layer 25 is, for example, 5 to 30.
nm. The antiferromagnetic layer 25 is made of, for example, Pt, Ru,
At least one of the group consisting of Rh, Pd, Ni, Au, Ag, Cu, Ir, Cr and Fe, M _II , and Mn
It is composed of an antiferromagnetic material including and. Of these, the Mn content is preferably 35 atom% or more and 95 atom% or less, and the content of the other element M _II is preferably 5 atom% or more and 65 atom% or less. This antiferromagnetic material exhibits antiferromagnetism without heat treatment, and exhibits a non-heat treatment type antiferromagnetic material that induces an exchange coupling magnetic field with the ferromagnetic material and an antiferromagnetism by heat treatment. There is a heat treatment type antiferromagnetic material. The antiferromagnetic layer 25 may be composed of either of them.

Non-heat-treatment type antiferromagnetic materials include Mn alloys having a γ phase. Specifically, RuRhMn,
There are FeMn, IrMn, and the like. The heat treatment type antiferromagnetic material includes Mn alloy having an ordered crystal structure and the like, and specifically includes PtMn, NiMn, PtRhMn and the like.

The thickness of the cap layer 26 is, for example, 4 to 6 n.
m. The material of the cap layer 26 is, for example, Ta.
Is used.

The bias magnetic field applying layer 18 shown in FIG.
It is composed of a hard magnetic layer (hard magnet), a laminated body of a ferromagnetic layer and an antiferromagnetic layer, and the like. Here, an example in which the bias magnetic field applying layer 18 is composed of a laminated body of a ferromagnetic layer arranged on the lower shield gap film 4 side and an antiferromagnetic layer formed on this ferromagnetic layer I will give you. In this case, the thickness of the ferromagnetic layer is, for example, 10 to 40n.
m. The ferromagnetic layer is made of, for example, NiFe, a laminated film of NiFe and CoFe, or a magnetic material containing at least one selected from the group consisting of Ni, Fe, and Co. The thickness of the antiferromagnetic layer is, for example, 10 to 20 nm. The antiferromagnetic layer may be made of, for example, a non-heat treatment type antiferromagnetic material or a heat treatment type antiferromagnetic material, but a nonheat treatment type antiferromagnetic material is preferable.

The bias magnetic field applying layer 18 is not limited to the above example, but may be a hard magnetic layer such as a laminated body of TiW and CoPt or a laminated body of TiW and CoCrPt.

The electrode layer 6 shown in FIG. 1 is a laminated body of Ta and Au, a laminated body of Tiw and Ta, or TiN and Ta.
It is composed of a laminated body or the like.

Next, the operation of the magnetoresistive device and the thin film magnetic head according to this embodiment will be described. The thin-film magnetic head records information on a recording medium by a recording head, and reproduces the information recorded on the recording medium by a magnetoresistive device which is a reproducing head.

Here, as shown in FIG. 2, the direction of the bias magnetic field by the bias magnetic field applying layer 18 of the magnetoresistive device is the X direction, and the direction perpendicular to the air bearing surface 30 is the Y direction. The X direction and the Y direction are orthogonal to each other. MR
In the element 5, in the absence of a signal magnetic field, the free layer 2
The magnetization direction of 2 is aligned with the X direction, which is the direction of the bias magnetic field. On the other hand, in the pinned layer 24, the ferromagnetic layer 2
The magnetization direction of 4c is fixed in the Y direction by the antiferromagnetic layer 25, and the magnetization direction of the ferromagnetic layer 24a is fixed in the ferromagnetic layer 2a.
It is fixed in the Y direction, which is the opposite direction to the magnetization direction of 4c.

In the MR element 5, the magnetization direction of the free layer 22 changes according to the signal magnetic field from the recording medium, whereby the magnetization direction of the free layer 22 and the magnetization of the ferromagnetic layer 24a of the pinned layer 24 are changed. The relative angle with respect to the direction changes, and as a result, the resistance value of the MR element 5 changes. The resistance value of the MR element 5 can be obtained from the potential difference between the two electrode layers 6 when a sense current is passed through the MR element 5 by the two electrode layers 6. In this way, the information recorded on the recording medium can be reproduced by the magnetoresistive device.

Next, the definition of the overlap amount of the electrode layer 6, which is one of the features of the magnetoresistive effect device and the thin film magnetic head according to the present embodiment, and the action and effect thereof will be described. In the following description, the two electrode layers 6 are both arranged so as to overlap the upper surface of the MR element 5, and the overlapping amount of each electrode layer 6 is 0.15 μm.
Less than and equal. Further, the overlap amount of the one electrode layer 6 in this case is L ₀ .

With the increase in recording density of hard disk devices, the thin film magnetic head is required to reduce the write track width and the read track width. Therefore, the effect of the overlap amount L ₀ of the electrode layer 6 in the magnetoresistive device on the read track width was examined by experiments. In this experiment, as shown in FIG. 7, the magnetoresistive device having a structure in which the two electrode layers 6 do not overlap the upper surface of the MR element 5, that is, the overlap amount L _0.
There the magnetoresistive device is zero, a magnetoresistive device structure in which two electrode layers 6 were overlapped on the upper surface of the MR element 5 together as shown in FIG. 8, the overlap amount L ₀ is 0. 05 μm, 0.10 μm, 0.15 μm,
Four kinds of 0.20 μm magnetoresistive effect devices were manufactured, and the output and the effective magnetic read track width (magnetic read width) were examined.

In the following description, as shown in FIGS. 7 and 8, the gap between two electrode layers 6 (hereinafter referred to as the electrode gap), which is the optical magnetic read track width, is denoted by the reference symbol MR.
The width on the upper surface of the MR element 5 (hereinafter referred to as the element width) is represented by T1 and is represented by the symbol MRT2. Further, the output of each magnetoresistive effect device expressed as a percentage based on the output of the magnetoresistive effect device with the overlap amount L ₀ shown in FIG. 7 being _zero is referred to as a normalized output, and is represented by the symbol Norm_TAA. Also,
The average value of the effective magnetic read track width (hereinafter referred to as the effective track width) is represented by the code MRW_mean, the standard deviation of the effective track width is represented by the code MRW_std, and the variation of the effective track width (3 times the standard deviation). ) Is represented by the code MRW_3std, and the maximum value of the effective track width expected from the variation in the effective track width is represented by the code MRW_max (3std).

The effective track width was measured from the full width at half maximum of the output when the output of the reproducing head was monitored by moving the thin film magnetic head in the track crossing direction.

In the experiment, the target value of the effective track width was set to 0.36 μm, and the electrode spacing MRT1 was set to 0.35 μm for all magnetoresistive devices. The experimental results are shown in the table below.

[0070]

[Table 1]

From this table, it can be seen that the output of the magnetoresistive device increases as the overlap amount L ₀ increases. When the overlap amount L ₀ is zero, the output is already improved by about 50% when the overlap amount L ₀ is 0.05 μm, and the output is about 2 when the overlap amount L ₀ is 0.20 μm. Has been doubled.

Here, with reference to FIGS. 9 and 10, the reason why the output of the magnetoresistive device increases due to the electrode layer 6 overlapping the MR element 5 will be described. FIG. 9 shows the flow of the sense current in the magnetoresistive device having a structure in which the two electrode layers 6 do not overlap the upper surface of the MR element 5. FIG. 10 shows the flow of the sense current in the magnetoresistive device having a structure in which the two electrode layers 6 both overlap the upper surface of the MR element 5.

As shown in FIGS. 9 and 10, since the bias magnetic field applying layers 18 are arranged on both sides of the MR element 5, the MR element 5 is near the end portion adjacent to the bias magnetic field applying layer 18. A region (hereinafter referred to as a dead region) 5B in which the direction of magnetization is fixed by the magnetic field from the bias magnetic field applying layer 18 and the signal magnetic field cannot be sensed.
Occurs. This dead region 5B does not contribute to the output of the magnetoresistive effect device. A region other than the dead region 5B of the MR element 5 is an activation region 5 capable of sensing a signal magnetic field.
It becomes A.

As shown in FIG. 9, in the magnetoresistive device having a structure in which the two electrode layers 6 do not overlap the upper surface of the MR element 5, the sense current passes through the two dead regions 5B, so that the output is descend. On the other hand, as shown in FIG. 10, in the magnetoresistive device having a structure in which the two electrode layers 6 both overlap the upper surface of the MR element 5,
Since the one electrode layer 6 exists even above the activation region 5A of the MR element 5, the ratio of the sense current passing through the dead region 5B is reduced as compared with the magnetoresistive device shown in FIG. In the magnetoresistive device shown in FIG. 10, particularly when the MR element 5 has a low resistance in response to a signal magnetic field, the current tries to pass through a place where the electric resistance is small. Attempts to pass only the activation region 5A. From the above, the electrode layer 6 is the MR element 5
The output of the magnetoresistive device increases due to the overlap.

As can be seen from the above table, the larger the overlap amount L ₀ , the larger the output of the magnetoresistive device. However, focusing on the effective track width required as the characteristic of the thin film magnetic head, it can be seen from the above table that the larger the overlap amount L ₀ , the more adversely affects the effective track width. In order to make this adverse effect easy to understand, the maximum value MRW_ma of the effective track width expected from the overlap amount L ₀ , the average value MRW_mean of the effective track width, and the variation of the effective track width.
The relationship with x (3std) is shown as a characteristic diagram in FIG. Figure 1
In FIG. 1, the solid line 31 also indicates the level of the target value (0.36 μm) of the effective track width. Further, as one of the standards required for the effective track width in order to secure the characteristics of the hard disk device, the effective track width is required to be within ± 15% of its target value. Therefore, the target value of the effective track width (0.36 μm)
The value of + 15% is the standard maximum value. In FIG. 11, reference numeral 3
The broken line indicated by 2 also indicates the level of the standard maximum value.

From the above table and FIG. 11, the electrode spacing MRT1
Is 0.35 μm and is constant, the mean value MRW_m of the effective track width increases as the overlap amount L ₀ increases.
It can be seen that the variation in ean and effective track width MRW_3std is large. One of the reasons why this phenomenon occurs is as follows. That is, when the overlap amount L ₀ increases, the electrode spacing MRT1 is constant but the element width MRT2 increases, so that the effect of the longitudinal bias magnetic field weakens, and as a result, the effective track width becomes unstable.

As can be seen from FIG. 11, when the overlap amount L ₀ is 0.15 μm, the average value MRW_mean of the effective track widths is extremely close to the standard maximum value, and the effective track widths expected from the variations in the effective track widths. Maximum value MR
W_max (3std) is about 0.03 μm larger than the standard maximum value. In this case, of all the manufactured heads, the ratio of the heads whose effective track width exceeds the standard maximum value is considerably large, and it is expected that the yield of the heads will be deteriorated.

When the overlap amount L ₀ becomes 0.20 μm, the average value MRW_mean of the effective track width exceeds the standard maximum value, and the maximum value MRW_max (3std) of the effective track width expected from the variation of the effective track width is It is about 0.09 μm larger than the standard maximum value and about 0.14 μm larger than the target value of the effective track width.

From the above, the electrode interval MRT1 is set to 0.35.
In the case of μm, it is not preferable to set the overlap amount L ₀ to 0.15 μm or more from the viewpoint of head yield.

If the electrode spacing MRT1 is smaller than 0.35 μm, it is possible to manufacture a head that meets the standard even if the overlap amount L ₀ is 0.15 μm or more. However, making the electrode interval MRT1 smaller than 0.35 μm imposes a heavy technical burden on the production of the electrode layer 6.

Therefore, from the viewpoint of the manufacturing technique of the electrode layer 6 and the yield of the head, the overlap amount L ₀ is 0.1.
It is preferably less than 5 μm.

As can be seen from FIG. 11, when the overlap amount L ₀ is 0.10 μm, the maximum value MR of the effective track width expected from the variation of the effective track width is MR.
W_max (3std) is slightly larger than the standard maximum value. Further, when the overlap amount L ₀ is 0.05 μm, the maximum value MRW_max (3std) of the effective track width expected from the variation of the effective track width becomes smaller than the standard maximum value. Therefore, for the purpose of improving the head yield, the overlap amount L ₀ is 0.10 μm.
It is preferably m or less, and more preferably 0.05 μm or less.

FIG. 12 is a characteristic diagram showing a correspondence relationship between the overlap amount L ₀ and the standardized output Norm_TAA. From this figure, it can be seen that the output can be improved if the overlap amount L _{0 is} small.

FIG. 13 is an enlarged characteristic diagram showing the range in which the overlap amount L ₀ in FIG. 12 is ₀ to 0.06 μm. Even if the output measurement error is estimated to be ± 5%, if the standardized output Norm_TAA is 105% or more, the output can be surely expected to be improved. The overlap amount L ₀ at which the normalized output Norm_TAA becomes 105% is about 0.003 μm. Therefore, the overlap amount L ₀ is preferably 0.003 μm or more.

Next, in the magnetoresistive device and the thin film magnetic head according to the present embodiment, the bias magnetic field applying layer 18 does not overlap the upper surface of the MR element 5, and the electrode layer 6 does not overlap the upper surface of the MR element 5. The action and effect of the wrapping will be described.

14 and 15 show two comparative magnetoresistive devices for the present embodiment. In the magnetoresistive device shown in FIG. 14, the bias magnetic field applying layer 18
Overlap with the upper surface of the MR element 5, but the electrode layer 6 does not overlap with the upper surface of the MR element 5.
In the magnetoresistive device shown in FIG. 15, both the bias magnetic field applying layer 18 and the electrode layer 6 overlap the upper surface of the MR element 5. As shown in FIGS. 14 and 15, when the bias magnetic field applying layer 18 overlaps the upper surface of the MR element 5, the bias magnetic field applying layer 18 is formed on the upper surface of the MR element 5 in the free layer of the MR element 5. A magnetic domain 5C having a magnetization direction opposite to the magnetization direction to be set by the bias magnetic field applying layer 18 is generated in a portion below the overlapping region. As a result, the occurrence rate of Barkhausen noise increases. In addition,
In FIG. 14 and FIG. 15, the arrow indicates the direction of magnetization.

As shown in FIG. 15, if both the bias magnetic field applying layer 18 and the electrode layer 6 are overlapped with the upper surface of the MR element 5, the ratio of the sense current passing through the magnetic domain 5C is reduced. As compared with the magnetoresistive device shown in FIG. 1, the occurrence rate of Barkhausen noise can be suppressed. However, even in the magnetoresistive device shown in FIG. 15, the bias magnetic field applying layer 18 does not overlap the upper surface of the MR element 5, but the electrode layer 6 overlaps the upper surface of the MR element 5. The occurrence rate of Barkhausen noise is higher than that of the magnetoresistive device.

An experiment was conducted to confirm the above. In this experiment, the relationship between the electrode spacing MRT1 and the occurrence rate of Barkhausen noise was examined for four types of magnetoresistive devices of types A, B, C, and D. In the following description, the length of the region where one of the bias magnetic field applying layers 18 overlaps the upper surface of the MR element 5 is called the overlap amount of the bias magnetic field applying layer 18, and is represented by L ₁ . In addition,
The overlap amount of the electrode layer 6 is L ₀ as in the above description.
It is represented by.

As shown in FIG. 7, the type A magnetoresistive device is a magnetoresistive device having a structure in which neither the bias magnetic field applying layer 18 nor the electrode layer 6 overlaps the upper surface of the MR element 5. In Type A, both L ₁ and L ₀ are 0.00 μm.

The type B magnetoresistive effect device is an example of the magnetoresistive effect device according to the present embodiment. In the type B magnetoresistive device, the bias magnetic field applying layer 18 is MR
The electrode layer 6 does not overlap the upper surface of the element 5 and is MR.
It overlaps with the upper surface of the element 5. In Type B, L ₁ is 0.00 μm and L ₀ is 0.10 μm.

As shown in FIG. 15, the type C magnetoresistive effect device is a magnetoresistive effect device having a structure in which both the bias magnetic field applying layer 18 and the electrode layer 6 overlap the upper surface of the MR element 5. In Type C, L ₁ is 0.08μ
m and L ₀ is 0.10 μm.

In the type D magnetoresistive device, as shown in FIG. 14, the bias magnetic field applying layer 18 overlaps the upper surface of the MR element 5, but the electrode layer 6 overlaps the upper surface of the MR element 5. It is a magnetoresistive device having an unwrapped structure. In Type D, L ₁ is 0.08 μm and L ₀ is 0.00 μm.

The following table and FIG. 16 show the experimental results for the relationship between the electrode spacing MRT1 and the occurrence rate of Barkhausen noise in the above four types of magnetoresistive devices. The numbers in the table below indicate the occurrence rate (%) of Barkhausen noise.

[0094]

[Table 2]

As can be seen from the above table and FIG. 16, in the range where the electrode spacing MRT1 is larger than 0.6 μm, there is no great difference in the Barkhausen noise occurrence rate among the four types of magnetoresistive effect devices. However, in the range where the electrode spacing MRT1 is 0.6 μm or less, the electrode spacing MRT1 becomes more remarkable as the electrode spacing MRT1 decreases.
There is a difference in the Barkhausen noise occurrence rate among the four types of magnetoresistive devices. When the electrode spacing MRT1 is 0.6 μm or less, type D, type A, type C, type B
In this order, the occurrence rate of Barkhausen noise increases. That is, in this range, the occurrence rates of Barkhausen noise in the type B magnetoresistive effect device, which is the magnetoresistive effect device according to the present embodiment, are of types A, C, and D.
It is lower than the occurrence rate of Barkhausen noise in the magnetoresistive device. Further, in this range, the occurrence rate of Barkhausen noise in the type B magnetoresistive device decreases as the electrode spacing MRT1 decreases.
On the other hand, the occurrence rate of Barkhausen noise in the type A, C, and D magnetoresistive devices increases as the electrode spacing MRT1 decreases.

In the type C and D magnetoresistive devices, the Barkhausen noise occurrence rate increases as the electrode spacing MRT1 becomes smaller. The reason why the electrode spacing MRT1 becomes smaller is the width of the magnetic domain 5C relative to the entire width of the MR element 5. It is considered that the ratio becomes large and the influence of the magnetic domain 5C increases. In the type A magnetoresistive device, the electrode spacing MR
The reason why the Barkhausen noise occurrence rate increases as T1 decreases is considered to be because the ratio of the width of the dead region to the entire width of the MR element 5 increases and the influence of the dead region increases as the electrode spacing MRT1 decreases. .

From the above experimental results, the magnetoresistive effect device according to the present embodiment can reduce Barkhausen noise as compared with the magnetoresistive effect devices of other structures such as types A, C, and D. I understand. Further, from this experimental result, it is understood that the magnetoresistive device according to the present embodiment has a remarkable effect of reducing Barkhausen noise when the electrode spacing MRT1 is 0.6 μm or less.

Next, the pinned layer 24 which is another characteristic of the magnetoresistive effect device and the thin film magnetic head according to the present embodiment.
The structure and the action and effect of it will be explained.

First, a magnetoresistive effect device of a comparative example manufactured for comparison with this embodiment will be described. The magnetoresistive device of the comparative example has a spin valve type GMR element including an ordinary pinned layer as the MR element. FIG. 17 shows the layer structure of the MR element 105 in the comparative example. The MR element 105 includes a base layer 121 and a free layer 12 which are sequentially stacked from the lower shield gap film side.
2, spacer layer 123, pinned layer 124, antiferromagnetic layer 1
25 and a cap layer 126. Pinned layer 1
Unlike the pinned layer 24 in the present embodiment, 24 does not have a non-magnetic spacer layer and is composed of only a ferromagnetic layer. Further, in the magnetoresistive effect device of the comparative example, as in the magnetoresistive effect device according to the present embodiment, the electrode layer is M
It has a structure that overlaps the upper surface of the R element,
The overlap amount is also equal to that in the present embodiment.

Next, the results of examining the Barkhausen noise occurrence rate of the magnetoresistive device of the comparative example and the magnetoresistive device according to the present embodiment will be described. The occurrence rate of Barkhausen noise was 15% in the magnetoresistive device of the comparative example, whereas it was 0% in the magnetoresistive device according to the present embodiment. From this, according to the magnetoresistive device according to the present embodiment,
It can be seen that Barkhausen noise can be sufficiently reduced.

The reason why Barkhausen noise can be sufficiently reduced by the magnetoresistive device according to the present embodiment will be described below with reference to FIGS. 18 to 20.

FIG. 18 shows the free layer 2 of the magnetoresistive device according to this embodiment and the magnetoresistive device of the comparative example.
It is a top view of 2,122. Since the bias magnetic field applying layers 18 are disposed on both sides of the MR elements 5 and 105, as shown in FIG. 18, the bias layers near the ends of the free layers 22 and 122 adjacent to the bias magnetic field applying layers 18 are biased. The direction of magnetization is fixed by the magnetic field from the magnetic field applying layer 18, and a dead region B where the signal magnetic field cannot be sensed is generated. The remaining region of the free layers 22 and 122 becomes the activation region A. However, in the case where the electrode layer has a structure in which it overlaps with the upper surface of the MR element, the electrode layer is present up to the activation region A, so that in the activation region A, the sense layer is formed near both ends thereof. Area A where current does not flow easily
₂ occurs. In the activation area A, the area between the _two areas A ₂ is an area A _{1 in} which a sense current often flows.

Further, in FIG. 18, the free layers 22 and 122 are
The magnetic field received by and its direction are indicated by arrows. In FIG. 18, the arrow indicated by reference numeral 41 indicates the longitudinal bias magnetic field and its direction, and the arrow indicated by reference numeral 42 indicates the pinned layers 24,
Represents the magnetic field and its direction, and the arrow indicated by reference numeral 43 represents the magnetic field generated by the sense current and its direction.

FIG. 19 is a plan view showing the magnetization state of the free layer 122 in the comparative example, and FIG. 20 is a plan view showing the magnetization state of the free layer 22 in the present embodiment. Figure 1
9 and 20, the arrows in the free layers 122 and 22 indicate the directions of magnetization. As shown in FIGS. 19 and 20, of the activation regions A in the free layers 122 and 22, the magnetization direction of the region A ₁ in which the sense current often flows coincides with the direction of the longitudinal bias magnetic field 41. However, the direction of magnetization in the region A ₂ where the sense current is hard to flow is
It is an intermediate direction between the direction of the longitudinal bias magnetic field 41 and the direction of the magnetic field 42 from the pinned layers 124 and 24. This is because the magnetic field 43 generated by the sense current is smaller in the area A ₂ where the sense current does not easily flow than in the area A ₁ , and is relatively strongly affected by the magnetic field 42 from the pinned layers 124 and 24. Is. In this way, the magnetization directions in the activation regions A in the free layers 122 and 22 are non-uniform.

As shown in FIGS. 19 and 20, the direction of magnetization of the region A ₂ in the present embodiment is longer than that of the region A ₂ in the comparative example by the longitudinal bias magnetic field 4.
Approaching direction 1. The reason is as follows. That is, in the pinned layer 24 in the present embodiment, since the two ferromagnetic layers 24a and 24c are antiferromagnetically coupled, the magnetic field generated by the pinned layer 24 is 2
It is closed so as to pass through the two ferromagnetic layers 24a and 24c. Therefore, the magnetic field generated by the pinned layer 24 in the present embodiment is the same as that in the normal pinned layer 1 in the comparative example.
The free layer 22, compared to the magnetic field generated by
The effect on 124 is reduced.

From the above, in the magnetoresistive effect device according to the present embodiment, the magnetization directions in the activation regions A in the free layers 122 and 22 are made uniform as compared with the magnetoresistive effect device in the comparative example. It As a result, in the magnetoresistive effect device according to the present embodiment, Barkhausen noise is further reduced as compared with the magnetoresistive effect device of the comparative example.

By the way, in the above description regarding the definition of the overlap amount of the electrode layers 6, both of the two electrode layers 6 are MR.
The electrodes 5 are arranged so as to overlap with the upper surface of the element 5, and the overlapping amounts of the respective electrode layers 6 are both less than 0.15 μm and equal. However, even if the head is designed in this way, the positions of the two electrode layers 6 may be displaced in the process of actually forming the electrode layers 6. As a result, as shown in FIG. 21, the two electrode layers 6 have different amounts of overlap, or in an extreme case, as shown in FIG. 22, only one of the electrode layers 6 has the MR element 5.
There may be a case where it overlaps with the upper surface of the.

Therefore, as shown in FIG. 21 and FIG.
A magnetoresistive device having different overlapping amounts of the two electrode layers 6 was manufactured, and an experiment was conducted to examine the influence on the characteristics of the head. In this experiment, the total length of the regions where the two electrode layers 6 overlap with one surface of the MR element 5 is 0.
Each magnetoresistive effect device shown in FIGS. 8, 21, and 22 was manufactured so as to have a constant value of less than 3 μm, and these characteristics were measured and compared. As a result, regarding the output of the magnetoresistive device, the average value of the effective track width, the variation of the effective track width (3 times the standard deviation) and the occurrence rate of Barkhausen noise, the magnetoresistive device shown in FIGS. Even in this case, it was found that the characteristics substantially equivalent to those of the magnetoresistive effect device shown in FIG. 8 can be obtained.

Therefore, in the present embodiment, at least one of the two electrode layers 6 overlaps one surface of the MR element 5, and the total overlapping amount of the two electrode layers 6 is 0.3 μm. It should be less than. For the purpose of improving the head yield, the total overlap amount is preferably 0.20 μm or less.
It is more preferable that the thickness is 10 μm or less. The total overlap amount is preferably 0.006 μm or more.

As described above, in the magnetoresistive device, the thin film magnetic head, and the manufacturing method thereof according to the present embodiment, the bias magnetic field applying layer 18 is provided so as to be adjacent to each side of the MR element 5. At least one of the two electrode layers 6 is arranged so as to overlap the upper surface of the MR element 5. As a result, according to the present embodiment, it is possible to reduce Barkhausen noise while preventing the output of the magnetoresistive effect device (reproducing head) from decreasing, and to improve the sensitivity of the magnetoresistive effect device (reproducing head). The output and output stability can be improved.

Further, according to the present embodiment, since the two bias magnetic field applying layers 18 are arranged so as not to overlap with the upper surface of the MR element 5, Barkhausen noise can be further reduced, and as a result, The output stability of the magnetoresistive device (reproducing head) can be further improved.

In this embodiment, the two electrode layers 6 are
Since the total overlap amount of the above is less than 0.3 μm, the effective read track width can be accurately determined.

Further, in the present embodiment, the electrode spacing MR
When T1 is 0.6 μm or less, the effect of reducing Barkhausen noise and improving the output stability of the magnetoresistive device (reproducing head) becomes remarkable.

In the present embodiment, the MR element 5 is
The pinned layer 24 is arranged so as to sandwich the non-magnetic spacer layer 24b and the non-magnetic spacer layer 24b, and the two ferromagnetic layers 24a, 24a whose magnetization directions are fixed in opposite directions to each other.
Since the spin valve type GMR element having a structure including 4c is used, Barkhausen noise can be sufficiently reduced and output stability can be further improved.

Next, referring to FIG. 23, the free layer 22 in the present embodiment will be described. FIG. 23 is a perspective view showing the structure of layers of the MR element according to the present embodiment. In the MR element 5 according to the present embodiment, the free layer 2
2 includes a first soft magnetic layer 22a, an intermediate layer 22b, and a second soft magnetic layer 22c that are sequentially stacked from the underlayer 21 side. The intermediate layer 22b is provided to increase the resistance change rate of the MR element 5.

The intermediate layer 22b may have, for example, a larger electric resistance than the first soft magnetic layer 22a and the second soft magnetic layer 22c and may have magnetism. In this case, the intermediate layer 22b increases the resistance change rate of the MR element 5 by reflecting at least a part of the electrons and limiting the path along which the electrons move when the sense current flows through the MR element 5. In this case, the thickness of the intermediate layer 22b is preferably 0.5 to 1 nm. The intermediate layer 22b preferably contains at least one kind of oxide, nitride, and oxynitride, for example. This is because it is magnetically stable and the output fluctuation can be reduced. The intermediate layer 22b preferably contains at least one of the constituent elements of the first soft magnetic layer 22a. This is because a good intermediate layer 22b can be easily obtained by oxidizing, nitriding, or oxidizing and nitriding a part of the first soft magnetic layer 22a. In addition, the intermediate layer 22b
May include at least one selected from the group consisting of Mn, Cr, Ni, Cu, Rh, Ir and Pt.

The intermediate layer 22b is the first soft magnetic layer 2
It may be a metal layer in which the elements forming 2a and the second soft magnetic layer 22c are diffused. In this case, the intermediate layer 22b
For example, a Ta film having a film thickness of 0.1 to 0.5 nm can be used. The intermediate layer 22b is made of Al,
Si, Ti, V, Cr, Mn, Ga, Ge, Y, Zr,
Nb, Mo, Ru, Rh, Pd, In, Sn, Hf, T
You may make it contain at least 1 sort (s) of the group which consists of a, W, Re, Os, Ir, and Pt. MR element 5
Annealing is performed after the formation of each of the layers constituting the first soft magnetic layer 22a by diffusing the elements constituting the first soft magnetic layer 22a and the second soft magnetic layer 22c into the intermediate layer 22b. The second soft magnetic layer 22c includes an intermediate layer 22b.
The metal element forming the element diffuses. Intermediate layer 22 in this case
b increases the resistance of the MR element 5 by increasing the sheet resistance of the free layer 22.

In the present embodiment, the intermediate layer 22
b is the middle of the first soft magnetic layer 22a or the second soft magnetic layer 2a.
It may be provided in the middle of 2c.

According to this embodiment, the resistance change rate of the MR element 5 can be increased.

Second Embodiment Next, with reference to FIG. 24, a magnetoresistive effect device and a thin film magnetic head according to a second embodiment of the invention, and a method for manufacturing them will be described. FIG. 24 is a perspective view showing the structure of layers of the MR element according to the present embodiment. In the MR element 65 in the present embodiment, the pinned layer 24 includes the reflective layer 24d. In the example shown in FIG. 24, the reflective layer 24d is arranged between the ferromagnetic layer 24a and the nonmagnetic spacer layer 24b.

The reflective layer 24d is composed of the ferromagnetic layers 24a and 24c.
It has a larger electric resistance and magnetism. The reflective layer 24d is provided when the sense current flows through the MR element 65.
The rate of change in resistance of the MR element 65 is increased by reflecting at least a part of the electrons and limiting the path along which the electrons move.

The thickness of the reflective layer 24d is preferably 0.5-1 nm. The reflective layer 24d preferably contains at least one kind of oxide, nitride, and oxynitride, for example. This is because it is magnetically stable and the output fluctuation can be reduced. The reflective layer 24d preferably contains at least one of the constituent elements of the ferromagnetic layer 24a. This is because a good reflective layer 24d can be easily obtained by oxidizing, nitriding, or oxidizing and nitriding a part of the ferromagnetic layer 24a. The reflective layer 24d preferably contains at least one selected from the group consisting of Mn, Cr, Ni, Cu, Rh, Ir, and Pt as an additive. This is because the thermal stability can be improved. Specifically, the reflective layer 24d includes at least Co selected from the group consisting of Ni, Co, and Fe, at least one selected from the group consisting of O and N, Mn, Cr, and
It preferably contains at least one selected from the group consisting of Ni, Cu, Rh, Ir and Pt.

The reflection layer 24d may be provided in the middle of the ferromagnetic layer 24a or the middle of the ferromagnetic layer 24c.

According to this embodiment, the resistance change rate of the MR element 65 can be increased. Other configurations, operations and effects in the present embodiment are similar to those in the first embodiment.

The present invention is not limited to the above-mentioned embodiments, and various modifications can be made. For example, the order of layers of the MR element may be opposite to that of the example shown in the embodiment.

Further, in the embodiment, the thin film magnetic head having the structure in which the reading magnetoresistive effect device is formed on the substrate side and the writing inductive type electromagnetic conversion element is laminated thereon is explained. The stacking order may be reversed.

When used as a read-only device, the thin-film magnetic head may be provided with only a read magnetoresistive device.

The magnetoresistive device of the present invention can be applied not only to the reproducing head of the thin film magnetic head, but also to a rotational position sensor, a magnetic sensor, a current sensor and the like.

[0129]

As described above, the magnetoresistive effect device according to any one of claims 1 to 5, and claim 6 to 1
20. A method of manufacturing a magnetoresistive device according to claim 0, a thin film magnetic head according to claim 11 or 15, or a method of manufacturing a thin film magnetic head according to claim 16. For example, a bias magnetic field applying layer is provided so as to be adjacent to each side of the magnetoresistive element,
Since at least one of the two electrode layers is arranged so as to partially overlap with one surface of the magnetoresistive effect element, the sensitivity, output and output stability of the magnetoresistive effect device or the thin film magnetic head are improved. There is an effect that it can be improved. Further, according to the present invention, since the total length of the regions where the two electrode layers overlap with one surface of the magnetoresistive effect element is set to less than 0.3 μm, the effective read track width can be accurately determined. Has the effect of becoming. Furthermore, according to the present invention, the magnetoresistive element is
Since it has a layer that restricts the path through which electrons move, it has the effect of increasing the rate of change in resistance of the magnetoresistive effect element.

A magnetoresistive device according to claim 5,
According to the method for manufacturing a magnetoresistive device according to claim 10, the thin-film magnetic head according to claim 15, or the method for manufacturing a thin-film magnetic head according to claim 20, the distance between the two electrode layers is set to 0.6 μm or less. Therefore, the effect of improving the output stability of the magnetoresistive device or the thin film magnetic head can be remarkably exhibited.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a cross section parallel to an air bearing surface of a magnetoresistive effect device according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a configuration of layers of the MR element according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view for explaining one step in the method of manufacturing the thin-film magnetic head according to the first embodiment of the invention.

FIG. 4 is a cross-sectional view for explaining a step following the step of FIG.

FIG. 5 is a cross-sectional view for explaining a step following the step of FIG.

FIG. 6 is a cross-sectional view of the thin film magnetic head according to the first embodiment of the invention.

FIG. 7 is an explanatory diagram showing a magnetoresistive device having a structure in which two electrode layers do not overlap the upper surface of the MR element.

FIG. 8 is an explanatory diagram showing a magnetoresistive device having a structure in which two electrode layers overlap with the upper surface of the MR element.

FIG. 9 is an explanatory diagram showing a sense current flow in a magnetoresistive device having a structure in which two electrode layers do not overlap the upper surface of the MR element.

FIG. 10 is an explanatory diagram showing the flow of a sense current in a magnetoresistive effect device having a structure in which two electrode layers both overlap the upper surface of the MR element.

FIG. 11 is a characteristic diagram showing a relationship between an overlap amount and an average value of effective track widths and a maximum value of effective track widths.

FIG. 12 is a characteristic diagram showing a correspondence relationship between an overlap amount and a standardized output.

FIG. 13 shows that the overlap amount in FIG.
It is a characteristic view which expands and shows the range of 06 μm.

FIG. 14 is an explanatory diagram showing a magnetoresistive device in which a bias magnetic field applying layer overlaps with the upper surface of the MR element, but an electrode layer does not overlap with the upper surface of the MR element.

FIG. 15 is an explanatory diagram showing a magnetoresistive device in which both a bias magnetic field applying layer and an electrode layer overlap the upper surface of the MR element.

FIG. 16 is a characteristic diagram showing the experimental results of examining the relationship between the electrode spacing and the Barkhausen noise occurrence rate for four types of magnetoresistive devices.

FIG. 17 is a perspective view showing a layer structure of an MR element in a comparative example.

FIG. 18 is a plan view of the free layer of the magnetoresistive effect device according to the first embodiment of the present invention and the magnetoresistive effect device of the comparative example.

FIG. 19 is a plan view showing a magnetization state of a free layer in a comparative example.

FIG. 20 is a plan view showing a state of magnetization of a free layer in the first embodiment of the invention.

FIG. 21 is an explanatory diagram showing a magnetoresistive effect device in which two electrode layers have different overlapping amounts.

FIG. 22 is an explanatory diagram showing a magnetoresistive device in which only one electrode layer overlaps the upper surface of the MR element.

FIG. 23 is a perspective view showing the configuration of layers of the MR element according to the first embodiment of the present invention.

FIG. 24 is a perspective view showing the configuration of layers of the MR element according to the second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Substrate, 2 ... Insulating layer, 3 ... Lower shield layer, 4 ... Lower shield gap film, 5,65 ... MR element, 6 ... Electrode layer, 7 ... Upper shield gap film, 8 ... Upper shield layer, 9 ... Recording gap layer, 11 ... First layer portion of thin film coil, 13 ... Second layer portion of thin film coil, 15 ... Upper magnetic pole layer, 16 ... Protective layer, 18 ... Bias magnetic field applying layer, 21 ...
Underlayer, 22 ... Free layer, 22a, 22c ... Soft magnetic layer,
22b ... intermediate layer, 23 ... spacer layer, 24 ... pinned layer,
24a ... Ferromagnetic layer, 24b ... Nonmagnetic spacer layer, 24c
... ferromagnetic layer, 24d ... reflective layer, 25 ... antiferromagnetic layer, 26
… Cap layer.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kenichi Takano             1-13-1, Nihonbashi, Chuo-ku, Tokyo             -In DC Inc. (72) Inventor Koichi Terunuma             1-13-1, Nihonbashi, Chuo-ku, Tokyo             -In DC Inc. (72) Inventor Joe Iwai             1-13-1, Nihonbashi, Chuo-ku, Tokyo             -In DC Inc. F-term (reference) 5D034 BA03 BA05 BA08 BA12 BA21                       BB08 CA04 CA08 DA07

Claims (20)

[Claims] 1. A magnetoresistive effect element having two surfaces facing each other and two side portions respectively connecting the two surfaces, and a magnetoresistive effect element adjacent to each side portion of the magnetoresistive effect element. Two bias magnetic field applying layers that are arranged to apply a bias magnetic field to the magnetoresistive effect element, and are arranged so as to be adjacent to one surface of each bias magnetic field applying layer. A magnetoresistive effect device comprising: two electrode layers for passing a current for signal detection, wherein at least one of the two electrode layers partially overlaps one surface of the magnetoresistive effect element. And a total length of a region in which the electrode layer overlaps one surface of the magnetoresistive effect element is less than 0.3 μm, and the magnetoresistive effect element has a non-magnetic surface having two surfaces facing to each other. Layer and before A soft magnetic layer disposed adjacent to one surface of the nonmagnetic layer, a pinned layer disposed adjacent to the other surface of the nonmagnetic layer and having a fixed magnetization direction, and the pinned layer. An antiferromagnetic layer which is arranged so as to be adjacent to the surface of the layer opposite to the nonmagnetic layer and fixes the direction of magnetization in the pinned layer, and at least when a current for signal detection flows through the magnetoresistive effect element. A magnetoresistive device comprising: a layer that reflects a part of electrons to limit a path along which the electrons move. 2. The magnetic layer according to claim 1, wherein the soft magnetic layer includes two layers, and the layer that restricts a path along which the electrons move is provided between the two layers. Resistance effect device. 3. The magnetoresistive device according to claim 1, wherein the pinned layer includes two layers, and the layer that restricts a path through which the electrons move is provided between the two layers. Effect device. 4. The two electrode layers are both arranged so as to partially overlap with one surface of the magnetoresistive effect element, and the length of the region in which each electrode layer overlaps with one surface of the magnetoresistive effect element is The magnetoresistive effect device according to any one of claims 1 to 3, wherein both are less than 0.15 µm. 5. The magnetoresistive device according to claim 1, wherein a distance between the two electrode layers is 0.6 μm or less. 6. A magnetoresistive effect element having two surfaces facing each other and two side portions respectively connecting the two surfaces, and adjacent to each side portion of the magnetoresistive effect element. Two bias magnetic field applying layers that are arranged to apply a bias magnetic field to the magnetoresistive effect element, and are arranged so as to be adjacent to one surface of each bias magnetic field applying layer. A method of manufacturing a magnetoresistive effect device, comprising: two electrode layers for passing a current for signal detection, the process comprising forming the magnetoresistive effect element; the process comprising forming the bias magnetic field applying layer; A step of forming a layer, at least one of the two electrode layers is arranged so as to partially overlap with one surface of the magnetoresistive effect element, and the electrode layer is provided on one side of the magnetoresistive effect element. Has a total length of less than 0.3 μm, and the magnetoresistive element is adjacent to one surface of the nonmagnetic layer having a nonmagnetic layer having two surfaces facing each other. And a soft magnetic layer arranged so as to be adjacent to the other surface of the non-magnetic layer, the pinned layer in which the magnetization direction is fixed, and the non-magnetic layer of the pinned layer on the opposite side. An antiferromagnetic layer which is arranged adjacent to the surface and fixes the direction of magnetization in the pinned layer, and at least a part of the electrons are reflected when a current for signal detection flows through the magnetoresistive element. A method of manufacturing a magnetoresistive device, comprising: a layer that restricts a moving path. 7. The magnetic layer according to claim 6, wherein the soft magnetic layer includes two layers, and the layer that restricts a path along which the electrons move is provided between the two layers. Method of manufacturing resistance effect device. 8. The magnetoresistive device according to claim 6, wherein the pinned layer includes two layers, and the layer that restricts a path along which the electrons move is provided between the two layers. Effect device manufacturing method. 9. The two electrode layers are arranged so as to partially overlap with one surface of the magnetoresistive effect element, and the length of the region where each electrode layer overlaps with one surface of the magnetoresistive effect element is Both are less than 0.15 micrometer, The manufacturing method of the magnetoresistive effect apparatus in any one of Claim 6 thru | or 8 characterized by the above-mentioned. 10. The distance between the two electrode layers is 0.6 μm.
The method for manufacturing a magnetoresistive device according to claim 6, wherein: 11. A magnetoresistive effect element having two surfaces facing each other and two side portions respectively connecting the two surfaces, and adjacent to each side portion of the magnetoresistive effect element. Two bias magnetic field applying layers that are arranged to apply a bias magnetic field to the magnetoresistive effect element, and are arranged so as to be adjacent to one surface of each bias magnetic field applying layer. A thin-film magnetic head having two electrode layers for passing a current for signal detection, wherein at least one of the two electrode layers partially overlaps one surface of the magnetoresistive element. The total length of the regions arranged so that the electrode layer overlaps one surface of the magnetoresistive effect element is less than 0.3 μm, and the magnetoresistive effect element has a non-magnetic layer having two surfaces facing each other. And before A soft magnetic layer disposed adjacent to one surface of the non-magnetic layer, a pinned layer disposed adjacent to the other surface of the non-magnetic layer and having a fixed magnetization direction, and the pinned layer. An antiferromagnetic layer which is arranged so as to be adjacent to the surface of the layer opposite to the non-magnetic layer and fixes the direction of magnetization in the pinned layer, and at least when a current for signal detection flows through the magnetoresistive element. A thin-film magnetic head having a layer that reflects a part of electrons and restricts a moving path of the electrons. 12. The thin film according to claim 11, wherein the soft magnetic layer includes two layers, and the layer that restricts a path along which the electrons move is provided between the two layers. Magnetic head. 13. The thin-film magnetic device according to claim 11, wherein the pinned layer includes two layers, and the layer that restricts a path through which the electrons move is provided between the two layers. head. 14. The two electrode layers are arranged so as to partially overlap with one surface of the magnetoresistive effect element,
14. The thin-film magnetic head according to claim 11, wherein the length of the region where each electrode layer overlaps one surface of the magnetoresistive effect element is less than 0.15 μm. 15. The distance between the two electrode layers is 0.6 μm.
The thin film magnetic head according to any one of claims 11 to 14, wherein: 16. A magnetoresistive effect element having two surfaces facing each other and two side portions respectively connecting the two surfaces, and a magnetoresistive effect element adjacent to each side portion of the magnetoresistive effect element. Two bias magnetic field applying layers that are arranged to apply a bias magnetic field to the magnetoresistive effect element, and are arranged so as to be adjacent to one surface of each bias magnetic field applying layer. A method of manufacturing a thin-film magnetic head, comprising: two electrode layers through which a current for signal detection is passed; a step of forming the magnetoresistive effect element; a step of forming the bias magnetic field applying layer; At least one of the two electrode layers is disposed so as to partially overlap with one surface of the magnetoresistive effect element, and the electrode layer is provided on one side of the magnetoresistive effect element. Has a total length of less than 0.3 μm, and the magnetoresistive element is adjacent to one surface of the nonmagnetic layer having a nonmagnetic layer having two surfaces facing each other. And a soft magnetic layer arranged so as to be adjacent to the other surface of the non-magnetic layer, the pinned layer in which the magnetization direction is fixed, and the non-magnetic layer on the opposite side of the non-magnetic layer in the pinned layer. An antiferromagnetic layer which is arranged adjacent to the surface and fixes the direction of magnetization in the pinned layer, and at least a part of the electrons are reflected when a current for signal detection flows through the magnetoresistive element. A method of manufacturing a thin-film magnetic head, comprising: a layer that restricts a moving path. 17. The thin film according to claim 16, wherein the soft magnetic layer includes two layers, and the layer that restricts a path through which the electrons move is provided between the two layers. Magnetic head manufacturing method. 18. The thin-film magnetic device according to claim 16, wherein the pinned layer includes two layers, and the layer that restricts the movement path of the electrons is provided between the two layers. Head manufacturing method. 19. The two electrode layers are arranged so as to partially overlap with one surface of the magnetoresistive effect element,
19. The method of manufacturing a thin-film magnetic head according to claim 16, wherein the lengths of the regions where each electrode layer overlaps one surface of the magnetoresistive effect element are both less than 0.15 μm. 20. The distance between the two electrode layers is 0.6 μm
20. The method of manufacturing a thin-film magnetic head according to claim 16, wherein: