JPH07220243A - Magneto-resistance effect type thin-film magnetic head and its production - Google Patents

Abstract

PURPOSE:To increase the recording density of a hard disk to >=2 times the current recording density and to stabilize reproducing operation by forming an antiferromagnetic film in contact with a part of a magneto-resistance effect magneto-sensitive part. CONSTITUTION:An MR element 6 is constituted by forming the MR magneto- sensitive part 14 laminated with a lower layer MR thin film 11 and an upper layer MR thin film 12 via a nonmagnetic film 13 on the antiferromagnetic film 15. The antiferromagnetic film 15 is in contact with the lower layer MR thin film 11. In such a case, magnetical coupling is formed between the lower layer MR thin film 11 and the upper layer MR thin film 12 and two layers of the MR thin films 11, 12 are respectively made into single domains. Movement of magnetic walls does not arise at the time of rotation of magnetization in the MR magneto-sensitive part 16 made into the single domains in such a manner and, therefore, the stable reproducing operation free from Barkhausen noises is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive thin film magnetic head suitable for reproducing a signal from, for example, a small-diameter hard disk.

[0002]

2. Description of the Related Art A hard disk device has been generally used as a storage device of a computer. In the field of computers in recent years, portable computers such as notebook computers have been developed, and even hard disk devices serving as storage devices are required to have smaller sizes and larger capacities in order to cope with such portable types. . Therefore,
For example, research has been conducted to reduce the disk size to 2.5 inches and obtain sufficient capacity and characteristics even in this case.

A problem in reducing the diameter of a disk is that, when the disk rotation speed is the same, the medium running speed becomes slower as the disk diameter becomes smaller, and in the magnetic induction type magnetic head, when the medium speed becomes slower, reproduction output is performed. Is to be smaller.

That is, in the past, as a recording / reproducing head of a hard disk device, a magnetic induction type magnetic head utilizing an electromagnetic induction phenomenon (hereinafter referred to as an inductive head).
Is used. To record an information signal with such an inductive head, an electric current is applied to the magnetic core in a direction corresponding to the recording signal, and an induction magnetic field generated by an electromagnetic induction phenomenon occurring at this time is applied to a hard disk serving as a medium. On the other hand, in order to reproduce, the magnetic flux leaking from the hard disk is picked up by the magnetic core, and the voltage change of the induced voltage generated by the electromagnetic induction phenomenon caused by the temporal change of the magnetic flux is converted into a signal.

Here, the magnitude of the induced voltage for reproducing by the electromagnetic induction phenomenon is not a magnitude of the magnetic flux but a value proportional to the rate of temporal change of the magnetic flux.
Therefore, if the medium traveling speed becomes too slow, the temporal change of the magnetic flux during reproduction becomes small, and the induced voltage becomes small. Therefore, in such a magnetic induction type magnetic head, when the medium traveling speed becomes slow, the reproduction output becomes small,
Therefore, the size reduction of the disk is limited.

Therefore, in recent years, in the hard disk drive, the inductive head is used as the recording head, but a magnetoresistive thin film magnetic head (hereinafter referred to as MR head) is used as the reproducing head. Has become.

This MR head is a reproducing head that utilizes the magnetoresistive effect phenomenon in which the electric resistance value changes depending on the angle formed by the direction of magnetization seen in a transition metal and the direction of the current flowing through the MR element. It has a magnetic thin film (hereinafter referred to as an MR thin film).

In the above-mentioned MR head, when the MR thin film receives a leakage magnetic flux from the magnetic recording medium, the magnetic flux causes the M
The direction of magnetization of the R thin film rotates, and the direction of the current flowing inside the MR thin film comes to have an angle corresponding to the magnetic amount. Therefore, the electric resistance value of the MR thin film changes, and a voltage change corresponding to the amount of change appears at the electrodes at both ends of the MR magnetic thin film through which a current is flowing, so that the magnetic recording signal is read as a voltage signal.

In the reproduction in which the resistance change according to the magnetic amount is detected as the reproduction output voltage, the reproduction output does not depend on the medium traveling speed, and regardless of whether the medium speed is small or large,
High playback output can be obtained. Therefore, it can be said that it is suitable for reducing the diameter of the disc.

For example, as a specific example of the MR head as described above, an MR element composed of an MR thin film in which a front end electrode (a magnetic recording medium contact surface side) and a rear end side are laminated with a front end electrode and a rear end electrode, respectively. And a bias conductor that gives the MR element a magnetization state in a desired direction is provided so as to cross the MR element, and the MR element and the bias conductor are sandwiched by a pair of shield magnetic bodies.
The head is known.

In this MR head, current from a DC power source is supplied from the terminal portions drawn out from the front and rear electrodes of the MR element to flow a sense current to the MR element, and at the same time, a DC current is supplied to the terminal portion of the bias conductor. A current is passed to give the MR element a magnetized state in a desired direction. As a result, signal reproduction is performed using the side edge of the MR element exposed on the contact surface of the magnetic recording medium as a reproduction gap.

In the MR head, if the MR thin film does not have a single domain structure during the reproducing operation, the domain wall moves when the magnetization rotates, and Barkhausen noise is generated. This movement of the domain wall occurs in order to maintain a state in which the sum of magnetostatic energy due to magnetic anisotropy energy, shape anisotropy, etc. is minimized in the entire layer.

Therefore, in the MR head, as shown in FIG.
As shown in FIG.
A non-magnetic film 203 is interposed between the two to form a vertical two-layer structure, so that a single domain structure can be obtained during a reproducing operation. The magnetization state of the MR element having the vertical two-layer structure is shown in FIGS. 13 (a) and 13 (b). It should be noted that this figure shows the case where the MR element is viewed from the contact surface side of the recording medium.

This MR element includes a lower MR thin film 201,
The upper MR thin film 202 is formed in a magnetic field to give induced magnetic anisotropy in the width direction. Lower and upper MR thin films 201 and 202 having induced magnetic anisotropy in the width direction
As shown in FIG. 13A, when the sense currents I _s1 and I _s2 are applied from the rear end side toward the recording medium contact surface side, they are mutually induced by the two MR thin films 201 and 202. Magnetic field H
₁ and H ₂ are generated. The induced magnetic fields H ₁ and H ₂ act as so-called stable bias magnetic fields, and the induced magnetic fields H ₁ and H ₂ cause the MR thin films 201 and 202 in the lower and upper layers to be formed as shown in FIG. 13B. induced magnetization M ₁ in anti-parallel to each other in, M ₂ occurs, the induced magnetization M _1, M
₂ magnetically _couple each other. As a result, a freewheeling magnetization in which the direction of magnetization is freewheeling is formed between the lower MR thin film 201 and the upper MR thin film 202, and two layers of M are formed.
The R thin films 201 and 202 each become a single magnetic domain.

In the MR element having a single magnetic domain as described above,
The operation mechanism can be described only by a macroscopic magnetization rotation mode. That is, in the MR element that is made into a single magnetic domain and has no domain wall, the only response to the change in the external magnetic field is the magnetization rotation without the domain wall movement. Therefore, Barkhausen noise does not occur and stable operation can be obtained.

[0016]

By the way, the vertical type 2
The layered MR element has an element width Tw, an element thickness t, an element length L, a distance l ₁ between a front electrode and a rear electrode, a front electrode length l ₂ ,
The magnetic characteristics are affected by the size of the rear end electrode length l _{3 and the} like. In particular, the element width Tw has a great influence on the above-mentioned single magnetic domain formation mechanism, and when the element width Tw is relatively wide, the single magnetic domain structure as described above can be formed, but in order to narrow the track width of the head, the element width Tw is reduced. When Tw is narrowed, it becomes difficult to form the above single magnetic domain. This causes a problem that the reproduction operation becomes unstable.

This is because the sense currents I _s1 and I _s2 are applied to the MR element.
Induced magnetic fields H ₁ , H generated by energizing
₂ is that the element side edge portion W _se is more dominant in the film thickness direction than in the width direction. For this reason, the magnetization dispersion becomes large, and the magnetization in the width direction becomes weak. In an MR element having a narrow element width Tw, the influence of this weak magnetization portion is large,
It becomes difficult to make the above mechanism into a single magnetic domain.

Therefore, the present invention has been proposed in view of such a conventional situation, and even when the track width is narrowed, a magnetoresistive thin film which can obtain a stable reproducing operation without Barkhausen noise is obtained. An object is to provide a magnetic head.

[0019]

In order to achieve the above object, a magnetoresistive thin film magnetic head of the present invention comprises a lower shield magnetic material and an upper shield magnetic material which are laminated on a substrate so as to face each other. In a magnetoresistive effect type thin film magnetic head having a magnetoresistive effect magnetic sensitive section made of a magnetoresistive effect thin film and a biasing conductor provided between, an antiferromagnetic film is provided in a part of the magnetoresistive effect sensitive section. It is characterized by being formed in contact with each other.

Further, the present invention is characterized in that an antiferromagnetic film is formed in contact with at least one of the upper side and the lower side of the magnetoresistive and magnetically sensitive portion. Further, the magnetoresistive effect magnetic sensing part is characterized in that two magnetoresistive effect thin films are laminated via an intermediate layer, and the intermediate layer is an antiferromagnetic film. Further, the thickness of the magnetoresistive effect thin film that constitutes the magnetoresistive effect magnetic field sensing portion is the thickness corresponding to the thickness that causes exchange interaction with the antiferromagnetic film, and is more than the optimum film thickness when the antiferromagnetic film is not formed. It is characterized by being made thick.

Further, the Nail point of the antiferromagnetic film is lower than the magnetic characteristic deterioration temperature of the magnetoresistive effect thin film forming the magnetoresistive effect magnetic sensitive section. Also,
A method of manufacturing a magnetoresistive thin film magnetic head according to the present invention,
When manufacturing a magnetoresistive thin-film magnetic head by forming a lower-layer shield magnetic body, a magnetoresistive magnetic sensitive section made of a magnetoresistive thin film, an antiferromagnetic film, a bias conductor, and an upper-layer shield magnetic body on a substrate, The magnetoresistive thin film and the antiferromagnetic film are formed so as to be in contact with each other, and then the magnetoresistive thin film and the antiferromagnetic film are heat-treated in a magnetic field.

Further, when the magnetoresistive effect thin film and the antiferromagnetic film formed in contact with each other are heat-treated in a magnetic field, the direction of the magnetic field is induced by applying a sense current to the magnetoresistive effect thin film. It is characterized in that the direction of the induced magnetic field is the same. Further, when a lower antiferromagnetic film, a magnetoresistive magnetic sensitive section made of a magnetoresistive thin film, and an upper antiferromagnetic film are sequentially formed in contact with each other, and heat treatment is performed in a magnetic field, the magnetic field is formed by It is characterized in that it is performed by passing a current in the same direction as the sense current through the resistance effect thin film.

Further, after sequentially forming a lower layer antiferromagnetic film, a magnetoresistive effect magnetic sensing portion composed of a magnetoresistive effect thin film, and an upper antiferromagnetic film in contact with each other, the magnetoresistive effect thin film in the same direction as the sense current is formed. When performing heat treatment while applying a current, the pattern shape of the lower antiferromagnetic film, the magnetoresistive effect magnetic sensitive part, and the upper antiferromagnetic film is set so that the element is cut out in the lengthwise direction. It is characterized in that it has a wide strip shape.

Further, when a lower magnetoresistive effect thin film, an antiferromagnetic film, and an upper magnetoresistive effect thin film are sequentially formed in contact with each other and heat-treated in a magnetic field, the magnetic field is formed by the lower magnetoresistive effect thin film and the upper layer magnetoresistive effect thin film. It is characterized in that the magnetoresistive effect thin film is formed by applying a current in the same direction as the sense current. Further, after sequentially forming the lower magnetoresistive thin film, the antiferromagnetic film, and the upper magnetoresistive thin film in contact with each other, a current in the same direction as the sense current is applied to the lower magnetoresistive thin film and the upper magnetoresistive thin film. While performing heat treatment, the lower magnetoresistive effect thin film, antiferromagnetic film,
It is characterized in that the pattern shape of the upper magnetoresistive thin film is a strip shape having a length in which a plurality of elements are cut out in the longitudinal direction and wider than the element.

[0025]

In the MR thin film, a pair of MR thin films sandwiching a non-magnetic film and an anti-ferromagnetic film in contact with the MR thin film are provided in the vicinity of the interface between the MR thin film and the anti-ferromagnetic film. In a MR element in which a fixed magnetization state is formed in the same direction as an induction magnetic field generated by applying a sense current, when a sense current is applied, a pair of MR thin films are formed by the induction magnetic field generated by the sense current and the fixed magnetization state. Induced magnetizations that are anti-parallel to each other occur.

Since this induced magnetization involves both the induced magnetic field by the sense current and the fixed magnetization state formed in the vicinity of the interface with the antiferromagnetic film, the strength is strong in the entire width direction. Therefore, a strong magnetic coupling is formed between the pair of MR thin films, and the two layers of MR thin films are made into single magnetic domains regardless of whether the element width is wide or narrow.

In the MR thin film having a single magnetic domain as described above,
Since the domain wall does not move when the magnetization is rotated, a stable reproducing operation without Barkhausen noise can be obtained.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described with reference to the drawings. The present embodiment is an example in which the present invention is applied to a composite type magnetic head having a structure in which an MR head is mounted as a reproducing head and an inductive head is mounted as a recording head.

As shown in FIG. 1, the composite magnetic head of this embodiment comprises an MR head 1 having a reproducing magnetic gap g ₁ facing the magnetic recording medium contact surface A, and the magnetic recording medium contact surface A. It is a so-called two-gap type recording / reproducing head in which the inductive head 2 facing the recording magnetic gap g ₂ is laminated on the slider 3 made of an Al ₂ O ₃ —TiC substrate or the like.

As shown in the sectional view of FIG. 2, the MR head 1 has a space between a lower shield magnetic body 4 and an upper shield magnetic body 5 formed on the slider 3 with an insulating layer 16 interposed therebetween. , The MR element 6 and the biasing conductor 7 (or hard film) are sandwiched, and one end of the MR element 6 is exposed at the contact surface A of the magnetic recording medium to form a reproducing gap g _1. It is like this.

The MR element 6 is formed in a rectangular pattern and is provided so that its longitudinal direction is orthogonal to the magnetic recording medium contact surface A, and one edge thereof is on the magnetic recording medium contact surface A. It is supposed to come.

The MR element 6 has a pair of electrodes (hereinafter, electrodes provided on the contact surface side of the magnetic recording medium) for passing a sense current from a constant current power source (not shown) at the front and rear ends, respectively. An electrode 8 and an electrode provided on the rear end side are referred to as a rear end electrode 9) are laminated.

The tip electrode 8 is formed, for example, as a wiring pattern having a substantially L-shaped plan view, one end of which is laminated on the tip of the MR element 6 and the MR element 6 is formed.
One side edge part of the pattern on the side to be laminated thereon is exposed to the magnetic recording medium contact surface A. The end of the wiring pattern that is pulled out from the tip electrode 8 to the back side serves as a ground side terminal. This ground is M
The role is to prevent the MR element 6 from being destroyed by the electrostatic potential (static electricity) generated when the R head 1 slides on the recording medium.

On the other hand, the rear end electrode 9 is formed as a wiring pattern having a substantially L shape in a plane like the front end electrode 8 and is provided on the half body side with the front end electrode 8 with the MR element sandwiched therebetween. It is laminated on the rear end of the MR element 6. The end portion of the wiring pattern drawn out from the rear end electrode 9 to the back side serves as a terminal portion on the DC power supply side. Therefore, when a direct current is supplied from the terminal portion of the rear end electrode 9, a sense current is supplied to the MR element 6 from the rear end side toward the front end side.

The biasing conductor 7 is formed as an elongated wiring pattern having a rectangular shape in a plan view, and is laminated on the MR element 6 with a predetermined distance therebetween via an insulating layer 10.

The bias conductor 7 is provided in a direction substantially orthogonal to the MR element 6, that is, in a form crossing the MR element 6. Then, this bias conductor 10
Both end portions of the are configured as terminal portions for passing a bias current from a DC power supply. Therefore, the direct current supplied from this terminal portion flows in the track width direction which is the longitudinal direction of the wiring pattern. As a result, a bias magnetic field is applied to the MR element 6 in a direction orthogonal to the contact surface A of the magnetic recording medium.
Applied to.

In the MR head, the MR element 6 is sandwiched between the lower shield magnetic body 4 and the upper shield magnetic body 5 made of a soft magnetic material such as permalloy with the insulating layer 10 interposed between them. Has become. The shield type configuration is used to improve the recording density dependency of the reproduction output.

The structure of the MR head has been described above. In this embodiment, in order to obtain a stable reproducing operation even when the element width Tw of the MR element 6 is narrowed, the MR head is designed to be stable.
As shown in FIG. 3, the element 6 is in contact with the MR magnetic sensing section 14 having a two-layer structure in which a lower MR thin film 11 and an upper MR thin film 12 are laminated with a non-magnetic film 13 interposed therebetween. The antiferromagnetic film 15 is provided as described above.

Hereinafter, the effect of providing the anti-ferromagnetic film 15 in contact with the MR magnetic sensing part 14 will be described. Before that, the MR characteristics of the MR element not using the anti-ferromagnetic film will be described. To do.

4A to 4D, the lower MR thin film 11 is formed.
And the external magnetic field dependence (MR curve) of the MR element of the vertical two-layer structure in which the non-magnetic film 13 is interposed between the MR thin film 12 and the upper MR thin film 12. The thickness of the MR element is 30 nm for both the lower MR thin film 11 and the upper MR thin film 12, and 6 nm for the non-magnetic film 13.
Is. The element length L is 5 μm, the distance l ₁ between the front electrode and the rear electrode is 2.5 μm, and the element width Tw is 5.0 μm, 3.5 μ.
m, 2.0 μm, and 1.0 μm. Figure 4 (a)
(D) shows the element width Tw of 5.0 μm, 3.5 μm,
The MR characteristics are shown when the thickness is 2.0 μm and 1.0 μm, respectively.

As can be seen from FIGS. 4 (a) to 4 (d),
M with element width Tw of 5.0 μm, 3.5 μm, 2.0 μm
With the R element, although MR characteristics without noise can be obtained,
In a MR element having a narrow element width Tw of 1.0 μm, Barkhausen noise is recognized and the reproducing operation becomes unstable.

Therefore, the self-bias effect due to the induced magnetic field of the sense current contributing to the single domain of the MR element was calculated. The result is shown in FIG.

The magnetic field is calculated by the magnetic permeability μs of the lower MR thin film 11 and the upper MR thin film 12 of 5000 and the film thickness of 30 n.
m, the thickness of the nonmagnetic film 13 is 6 nm, and the element length L is 10
0 μm, element width Tw of 5.0 μm, 3,5 μm, 2.0
It was performed assuming that the value was changed to μm. A typical value of the sense current density was 0.033 TA / m ² . FIG. 5 also shows the results when the element widths are set. In FIG. 5, the horizontal axis is the track width and the vertical axis is Bx.

From FIG. 5, in the case of any MR element,
It can be seen that the magnetization does not reach saturation within the range of 1 μm on the side edge.

Here, when the element width Tw is relatively wide, the ratio of the portion where the magnetization is saturated is large. Therefore, magnetic coupling of magnetization in the width direction can be formed, and a single domain structure can be obtained. Therefore, it is presumed that noise was not recognized in the MR characteristics.

On the other hand, when the element width Tw is narrow, the magnetization becomes unsaturated in the entire width direction. This is because the demagnetizing field in the width direction increases as the element width Tw decreases.
It is considered that Barkhausen noise appears in the MR characteristics because the lack of magnetization does not lead to single domain formation.

Therefore, in the head of this embodiment, by using the antiferromagnetic film 15, a fixed magnetic field state acting as a stabilizing bias magnetic field is formed in the MR magnetic sensing section 14, and this is magnetically coupled. To contribute to. This prevents Barkhausen noise that occurs when the element width is narrow.

The formation of a fixed magnetic field state by the antiferromagnetic film 15 will be described with reference to FIGS. 6A to 6C by taking a thin film sample in which an antiferromagnetic film is laminated on an MR thin film as an example. To do. It is assumed that the MR thin film is provided with induced magnetic anisotropy in the width direction by forming the film in a magnetic field.

As shown in FIG. 6A, the MR thin film 101
In the thin film sample in which the antiferromagnetic film 102 is laminated on the
In the initial stage, each spin 104 in the antiferromagnetic film 102 is Ant
The MR thin film 101 is in the i-Ferro coupling state.
Has induced magnetic anisotropy in the same direction as that applied during film formation.

The thin film sample in such a magnetized state is subjected to heat treatment at a temperature not lower than the Neel temperature of the antiferromagnetic film while applying an external magnetic field in the width direction. Then, as shown in FIG. 6B, the spins 104 in the antiferromagnetic film 102 are in a disordered thermal oscillation state, and the MR thin film 101 is magnetized in a direction parallel to the external magnetic field applied at that time. To be done.

After that, the thin film sample is cooled to room temperature while applying an external magnetic field. Then, as shown in FIG.
As shown in (c), the antiferromagnetic film 102 and the MR thin film 10
1 near the boundary surface 105, that is, 5 nm from the boundary surface
Except for some parts, the antiferromagnetic film 102 and the MR thin film 10
The magnetization state of 1 returns to the initial state, and the vicinity of the interface 105 becomes a fixed magnetization state M ′ in which spins are Ferro-coupled to each other. This fixed magnetization state M ′ is generally referred to as spin pinning, and is equivalent to constantly applying a magnetic field.

In the head of this embodiment, a fixed magnetization state is formed in the MR magnetic sensitive section 14 by the antiferromagnetic film 15 by the mechanism as described above, and this is acted as a stabilizing bias magnetic field to form a single domain structure. I decided to.

That is, as shown in FIG. 3, the MR element 6 includes an antiferromagnetic film 15, a lower MR thin film 11 and an upper MR film.
An MR magnetic sensing section 14 is formed by laminating thin films 12 with a non-magnetic film 13 interposed therebetween, and an antiferromagnetic film 15 is in contact with the lower MR thin film 11. In the MR element 6 having such a structure, as shown in FIG. 7A, the sense currents I _s1 and I _s2 , which are energized during the reproducing operation, are generated in the vicinity of the interface between the lower MR thin film 11 and the antiferromagnetic film 15. A fixed magnetization state M ₂ ′ is formed in the same direction as the induced magnetic field H ₂ generated.

In the MR sensitive section 14 in which such a fixed magnetization state M ₂ ′ is formed in the lower MR thin film 11, when the sense currents I _s1 and I _s2 are applied to the lower MR thin film 11 and the upper MR thin film 12, this occurs. Induced magnetic fields H ₁ and H ₂ generated by
Due to this fixed magnetization state M ₂ ′, induction magnetizations M ₁ and M _{2 that} are antiparallel to each other are generated in the two layers of MR thin films 11 and 12, as shown in FIG. 7B.

The induced magnetizations M ₁ and M ₂ are the sense current I
_s1, the induced magnetic field H _1, H ₂ by I _s2, since both of the antiferromagnetic film fixed magnetization formed at the interface vicinity of the M ₂ 'is involved, intensity across the entire width strong. Therefore, regardless of whether the element width Tw is wide or narrow, magnetic coupling is formed between the lower MR thin film 11 and the upper MR thin film 12, and the two MR thin films 11 and 12 are each made into a single magnetic domain.

The MR magnetic sensing section 16 thus formed into a single magnetic domain.
Then, since the domain wall does not move when the magnetization is rotated,
A stable operation without Barkhausen noise means that a reproducing operation can be obtained.

The structure of the MR element 6 is not limited to the above-described structure, but conversely, the antiferromagnetic film 15 may be laminated on the MR sensitive section 14, or both the upper and lower sides of the MR sensitive section 14. Alternatively, the antiferromagnetic film 15 may be formed. Further, the antiferromagnetic film 1 is provided between the lower MR thin film 11 and the upper MR thin film 12.
5 may be interposed. In this case, since the antiferromagnetic film 15 also functions as a non-magnetic film, the non-magnetic film 13 need not be interposed between the lower MR thin film 11 and the upper MR thin film 12 of the MR sensitive section 14. .

In the MR element having the structure in which the antiferromagnetic film 15 is laminated on the upper surface of the MR magnetic sensing part 14, the upper MR thin film 12 is in contact with the antiferromagnetic film 15. Therefore, in the vicinity of the interface between the upper MR thin film 12 and the antiferromagnetic film 15, the fixed magnetization state M ₁ ′ in the same direction as the induced magnetic field H ₁ generated by the sense currents I _s1 and I _s2 , that is, the MR magnetic sensing section 14 is generated. A fixed magnetization state M ₁ ′ is formed in the opposite direction to the case where the antiferromagnetic film 15 is formed on the lower side.

The antiferromagnetic film 1 is formed on both upper and lower sides of the MR magnetic sensing section 14.
In the MR element having the structure of 5, the lower MR thin film 11,
Both of the upper MR thin films 12 are in contact with the antiferromagnetic film 15.
Therefore, as shown in FIG. 8A, this lower MR thin film 1
1, an induction magnetic field H ₁ generated by the sense currents I _s1 and I _{s2 in the} vicinity of the interface between the upper MR thin film 12 and the antiferromagnetic film 15,
The fixed magnetization states M ₁ ′, M ₂ ′ in the same direction as H ₂ , that is, the fixed magnetization state M ₂ in the right direction in the figure for the lower MR thin film 11 are shown.
′ ′, A fixed magnetization state M ₁ ′ is formed in the upper MR thin film 12 in the leftward direction in the figure.

Further, in the MR element having the structure in which the antiferromagnetic film 15 is interposed between the lower MR thin film 11 and the upper MR thin film 12, both the lower MR thin film 11 and the upper MR thin film 12 have the antiferromagnetic film 15 as well. Contact with. Therefore, FIG.
As shown in (a), fixed in the same direction as the induced magnetic fields H ₁ and H ₂ generated by the sense currents I _s1 and I _s2 near the interface between the lower MR thin film 11 and the upper MR thin film 12 and the antiferromagnetic film 15. The magnetization states M ₁ ′ and M ₂ ′, that is, the fixed magnetization state M ₂ ′ facing right in the figure is shown in the upper MR layer 11 in the lower MR thin film 11.
In the R thin film 12, a fixed magnetization state M ₁ ′ is formed facing left in the figure.

As shown in FIGS. 8A and 9A, the MR element having the fixed magnetization states M ₁ ′ and M ₂ ′ has a lower MR layer.
When sense currents I _s1 and I _s2 are applied to the thin film 11 and the upper MR thin film 12, induced magnetic fields H ₁ and H generated by the sense currents I _s1 and I _s2 are generated.
₂ and this fixed magnetization state M ₁ ′,
As shown in FIGS. 9B and 9B, the two-layer MR thin film 1
Induced magnetizations M ₁ and M _{2 that} are antiparallel to each other are generated in ₁ and 12.

The induced magnetizations M ₁ and M ₂ are the sense current I
_s1, the induced magnetic field H _1, H ₂ by I _s2, since both of the antiferromagnetic film and the pinned magnetization state M ₁ formed on the boundary surface neighborhood of 'is involved, intensity across the entire width strong. Therefore, regardless of whether the element width Tw is wide or narrow, a strong magnetic coupling is formed between the lower MR thin film 11 and the upper MR thin film 12, and the two MR thin films 11 and 12 are each made into a single magnetic domain. Therefore, a stable reproducing operation without Barkhausen noise can be obtained.

As a material used for the MR thin films 11 and 12, a soft magnetic material such as permalloy which is usually used in an MR head may be used, but antiferromagnetism is used when forming the fixed magnetization state. Due to the fact that a temperature above the Neel point of the film is applied, it is desirable to select one that is excellent in thermal stability and one that does not cause deterioration of magnetic properties at a temperature at least around the Neel point.

The antiferromagnetic film 15 is made of Fe.
Mn, NiO, NiCoO, etc. are mentioned. this house,
NiO has a Neel point of 250 ° C., and in such a Neel point, a heat treatment temperature of about 280 ° C. is suitable for forming a fixed magnetization state.

In the MR magnetic thin films 11 and 12 in which the fixed magnetization state is formed by the antiferromagnetic film 15 as described above, the magnetization does not rotate in the portions having the fixed magnetization states M ₁ ′ and M ₂ ′. It does not contribute to the resistance change in the magnetoresistive effect. Therefore, the film thicknesses of the MR magnetic thin films 11 and 12 are equal to the film thicknesses of the fixed magnetization states M ₁ ′ and M ₂ ′, as compared with the optimum film thicknesses when the fixed magnetization states M ₁ ′ and M ₂ ′ are not formed. It is preferable to make it thick. Usually, the fixed magnetization states M ₁ ′ and M ₂ ′ are about 5 nm from the interface with the antiferromagnetic film 15, and the MR magnetic thin films 11 and 12 may be formed thicker by this amount. For example, 20 nm when the optimum film thickness when the fixed magnetization state is not formed is 15 nm
Design the film thickness to some extent.

To form the MR element 6, the lower MR
The thin film 11, the non-magnetic film 13, the upper MR thin film 12, and the antiferromagnetic film 15 are continuously formed in the order according to the structure,
Patterning into a predetermined element shape is performed by a dry etching process.

Then, the patterned element is
Heat treatment is performed in a constant-temperature furnace while applying a magnetic field. As a result, the fixed magnetization state M in which spins are pinned near the boundary surface between the MR magnetic thin films 11 and 12 and the antiferromagnetic film 15 is obtained.
₁ ', M _2' is formed. However, the direction of the magnetic field applied during the heat treatment, the fixed magnetization state M ₁ ', M _2' because it determines the magnetization direction of the fixed magnetization state M ₁ acting as a stabilizing bias field ', M _2' to obtain the , And the directions of the induced magnetic fields H ₁ and H ₂ by the sense currents I _s1 and I _s2 need to match.

Here, the antiferromagnetic film 15 is the MR magnetic sensing portion 14.
MR element 6 having a structure formed on either the upper side or the lower side of the
In the case of, the lower MR thin film 11 as shown in FIG.
Alternatively, in any of the upper MR thin films 12, a fixed magnetization state M
Since it is sufficient to form ₁ ′ and M ₂ ′, the sense current I _s1 ,
When I _s2 is energized, its fixed magnetization state M ₁ ′, M ₂
It is only necessary to apply a DC magnetic field from the outside in a direction coinciding with the direction of the induced magnetic field H ₁ or H ₂ generated in the MR thin film forming ′ ′.

On the other hand, the antiferromagnetic film 15 is formed on the upper and lower sides of the MR sensitive section 14, the MR element, the lower MR thin film 11,
In the MR element having the structure in which the antiferromagnetic film 15 is interposed between the upper MR thin films 12, as shown in FIGS. 8A and 9A, the lower MR thin film 11 and the upper MR thin film 12 are respectively formed. The fixed magnetization states M ₁ ′ and M ₂ ′ are formed. In the lower MR thin film 11 and the upper MR thin film 12, the sense currents I _s1 and I _s2
Since the directions of the induced magnetic fields H ₁ and H ₂ when the current is passed through are opposite to each other, the fixed magnetization state M ₁ ′,
In order to form M ₂ ′, it is necessary to apply opposite magnetic fields to the lower MR thin film 11 and the upper MR thin film 12 during the heat treatment.

In such a case, a magnetic field is not applied from the outside, but a current is applied to the lower MR thin film 11 and the upper MR thin film 12 in the same direction as the sense currents I _s1 and I _s2, and the induction generated thereby A fixed magnetic state may be formed by a magnetic field.

When a magnetic field is formed by energizing the lower MR thin film 11 and the upper MR thin film 12 in this way, patterning is not performed in the element shape, but FIGS.
As shown in [however, FIG. 10 (b) is an enlarged view of a portion surrounded by a circle in FIG. 10 (a)], a length such that a plurality of MR elements 6 are cut out in the longitudinal direction. The plurality of strips 111 each having a width wider than the width of the element are electrically connected to each other at both ends thereof. Then, a DC power source is connected, and a current I is applied to the strip 111 in a direction coinciding with the sense current. As a result, the fixed magnetization states M ₁ ′ and M ₂ are simultaneously applied to a plurality of MR elements.
′ Can be formed.

M subjected to the heat treatment in the magnetic field as described above
The MR curve of the R element is shown in FIG. 11 (b), and the MR curve of the MR element before the heat treatment in the magnetic field is shown in FIG. 11 (a). The MR element is composed of a lower MR thin film 11 and an upper MR thin film 12.
Are laminated via the NiO antiferromagnetic film 15. The film thickness composition is the lower MR thin film 11 and the upper MR thin film 12.
Is 20 nm, and the antiferromagnetic film 15 is 15 nm. The element length L is 10 μm, the element width Tw is 1 μm, and the distance l ₁ between the front electrode and the rear electrode is 5 μm.

In the heat treatment in the magnetic field, a magnetic field is applied to the lower MR thin film 1.
1. It was generated by passing a current in the same direction as the sense currents I _s1 and I _s2 through the upper MR thin film 12, heat-treated at 280 ° C. for 1 hour in this magnetic field, and then cooled. Regarding the MR characteristics, while applying a sense current of 6 mA to the MR element, an external parallel magnetic field of about ± 100 Oe is applied from the front end side to the rear end side according to the signal magnetic field from the medium,
It was investigated by measuring the resistance value of the MR element at that time by a DC 4-terminal method.

As can be seen by comparing FIGS. 11A and 11B, the MR element after the heat treatment in the magnetic field has a smaller Δρ / ρ and a slightly lower element sensitivity than the MR element before the treatment. However, the element anisotropic magnetic field Hk is large and Barkhausen noise disappears. From this, it is understood that forming a fixed magnetic field state in the MR element is effective in stabilizing the reproducing operation.

The magnetic head of this embodiment is constructed by laminating the inductive head on the MR head which is stable in operation as described above.

In the inductive head, as shown in FIG. 1, the upper shield magnetic body 5 is used as the other thin film magnetic core forming a closed magnetic path, and the third thin film magnetic core is laminated so as to face the upper shield magnetic body 5. The recording magnetic gap g ₂ is formed between the front end of the magnetic recording medium facing surface A and the front surface thereof. That is, the third thin film magnetic core 31 laminated so as to face the upper shield magnetic body 5 is bent toward the upper shield magnetic body 5 at the front end facing the recording medium contact surface A, and the gap is A recording magnetic gap g ₂ is formed in the narrowed facing portion. The third thin film magnetic core 31
Is configured to magnetically contact the upper shield magnetic body 5 at the rear end to form a back gap.

The magnetic coupling portion, which is the connection portion between the third thin film magnetic core 31 and the upper shield magnetic body 5, is
A spiral head winding 32 is provided so as to surround the magnetically coupled portion. The head winding 32 is
In order to secure the insulation between the third thin film magnetic core 31 and the upper shield magnetic body 5, it is embedded with an insulating layer. In addition, the winding start and end ends 32a and 32b of the head winding 32 serve as terminals for passing a recording current from an AC power supply supplied to the head winding. An insulating layer 34 functioning as a protective film for protecting the MR head 1 and the inductive head 2 is provided on the third thin film magnetic core 31.

The composite type magnetic head having the above structure is
Since the reproducing head is an MR head using an antiferromagnetic film, a large reproducing output can be obtained even when the diameter of the disk is reduced, and a stable reproducing operation is performed even when the track width is narrowed to about 1.0 μm. Is obtained. Therefore, it greatly contributes to miniaturization and large capacity of the hard disk.

[0079]

As is clear from the above description, in the magnetoresistive thin film magnetic head of the present invention, since the antiferromagnetic film is in contact with the MR magnetic sensitive portion, the track width is 1.0 μm.
Even when the size is reduced to about m, a stable reproducing operation without Barkhausen noise can be obtained. Therefore, according to the magnetoresistive thin-film magnetic head of the present invention, it is possible to increase the recording density of the hard disk more than twice the current density, which contributes to the further reduction in size and capacity of the hard disk device.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing a partially broken composite magnetic head equipped with an MR head to which the present invention is applied.

FIG. 2 is a schematic sectional view of the MR head.

FIG. 3 is a perspective view showing a configuration example of an MR element.

FIG. 4 MR of MR element without antiferromagnetic film formed
It is a characteristic diagram showing characteristics, (a) is an element width of 5.0μm
MR characteristics in the case of, element (b) is MR characteristics when the element width is 3.5 μm, (c) is MR characteristics when the element width is 2.0 μm
The characteristic, (d) is the MR characteristic when the element width is 1.0 μm.

FIG. 5 is a characteristic diagram showing the relationship between the track width and Bx of an MR element in which an antiferromagnetic film is not formed.

FIG. 6 is a schematic diagram showing a fixed magnetization state forming mechanism of a thin film sample in which an antiferromagnetic film is formed on an MR thin film,
(A) is an initial magnetization state, (b) is a magnetization state when heat-treated in a magnetic field, and (c) is a magnetization state when heat-treated in a magnetic field and then cooled.

7A and 7B are schematic diagrams showing the magnetization state of the MR element of FIG. 3, in which FIG. 7A shows a fixed magnetization state and an induced magnetic field induced by energization of a sense current, and FIG. 7B shows a fixed magnetization state. And the state of magnetization of the MR thin film by the induced magnetic field.

FIG. 8 is a schematic view showing a magnetized state of an MR element formed by forming antiferromagnetic films on both upper and lower sides of an MR magnetic sensing part,
(A) shows a fixed magnetization state and an induction magnetic field induced by energization of a sense current, and (b) shows a fixed magnetization state and a state of magnetization of the MR thin film due to the induction magnetic field.

FIG. 9 shows an M having a structure in which an antiferromagnetic film is sandwiched between MR thin films.
It is a schematic diagram which shows the magnetization state of R element, (a) shows a fixed magnetization state and the induction | guidance | derivation magnetic field induced by energization of a sense current, (b) is a fixed magnetization state and the MR thin film by an induction | guidance magnetic field. The state of magnetization is shown.

FIG. 10 is a plan view showing an example of a pattern of an MR element that is heat-treated in a magnetic field.

11A and 11B are characteristic diagrams showing MR characteristics of the MR element of FIG. 9, where FIG. 11A is an MR characteristic before heat treatment in a magnetic field, and FIG. 11B is an MR characteristic after heat treatment in a magnetic field.

FIG. 12 is a perspective view showing a conventional MR element.

FIG. 13 is a schematic diagram showing a magnetized state of a conventional MR element, (a) shows an induced magnetic field induced by a sense current, and (b) shows a state of magnetization of an MR thin film by the induced magnetic field. It is shown.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 MR head 4 Lower shield magnetic body 5 Upper shield magnetic body 6 MR element 7 Bias conductor 11 Lower MR thin film 12 Upper MR thin film 13 Non-magnetic film 14 MR magnetic sensitive section 15 Antiferromagnetic film

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Junichi Sugawara 6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Within Sony Corporation (72) Inventor Norio Saito 6-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation

Claims (11)

[Claims] 1. A magnetoresistive effect magnetic sensing part made of a magnetoresistive effect thin film and a biasing conductor are provided between a lower shield magnetic material and an upper shield magnetic material, which are laminated on a substrate so as to face each other. A magnetoresistive thin-film magnetic head, characterized in that an antiferromagnetic film is formed in contact with a part of the magnetoresistive magnetic sensitive portion. 2. The magnetoresistive thin-film magnetic head according to claim 1, wherein an antiferromagnetic film is formed in contact with at least one of the upper side and the lower side of the magnetoresistive magnetic sensing section. 3. The magnetoresistive effect magnetic sensing part is formed by laminating two layers of magnetoresistive effect thin films via an intermediate layer, and the intermediate layer is an antiferromagnetic film. Magnetoresistive thin film magnetic head. 4. An optimum film in the case where the antiferromagnetic film is not formed by the thickness of the magnetoresistive thin film forming the magnetoresistive magnetic sensitive part by the thickness of exchange interaction with the antiferromagnetic film. The magnetoresistive thin-film magnetic head according to claim 1, wherein the magnetoresistive thin-film magnetic head is thicker than the thickness. 5. The magnetoresistive thin film according to claim 1, wherein the Neel point of the antiferromagnetic film is lower than the magnetic characteristic deterioration temperature of the magnetoresistive thin film forming the magnetoresistive magnetic sensitive section. Magnetic head. 6. A magnetoresistive thin-film magnetic head in which a lower shield magnetic body, a magnetoresistive magnetic sensing portion made of a magnetoresistive thin film, an antiferromagnetic film, a bias conductor, and an upper shield magnetic body are formed on a substrate. When manufacturing the magnetoresistive effect thin film and the antiferromagnetic film, the magnetoresistive effect thin film and the antiferromagnetic film are heat-treated in a magnetic field after being formed so as to be in contact with each other. 2. A method of manufacturing a magnetoresistive thin film magnetic head as described in 1. 7. When the magnetoresistive thin film and the antiferromagnetic film formed in contact with each other are heat-treated in a magnetic field, the direction of the magnetic field is induced by applying a sense current to the magnetoresistive thin film. 7. The method of manufacturing a magnetoresistive thin-film magnetic head according to claim 6, wherein the direction of the induced magnetic field is the same. 8. A magnetic field is formed when a lower layer antiferromagnetic film, a magnetoresistive effect magnetic sensing part composed of a magnetoresistive thin film, and an upper antiferromagnetic film are sequentially formed in contact with each other, and heat treatment is performed in a magnetic field. 8. The method of manufacturing a magnetoresistive thin-film magnetic head according to claim 7, wherein the magnetoresistive thin film is applied with a current in the same direction as a sense current. 9. A lower antiferromagnetic film, a magnetoresistive effect magnetic sensing part composed of a magnetoresistive effect thin film, and an upper antiferromagnetic film are sequentially formed so as to be in contact with each other. The pattern shape of the lower antiferromagnetic film, the magnetoresistive effect magnetic sensitive area, and the upper antiferromagnetic film, which are subjected to heat treatment while applying a current, is the length at which the element is cut out in the longitudinal direction. 9. The method for manufacturing a magnetoresistive effect thin film magnetic head according to claim 8, wherein the strip is wider than the element. 10. A lower magnetoresistive effect thin film, an antiferromagnetic film,
When sequentially forming the upper magnetoresistive thin films in contact with each other and performing heat treatment in a magnetic field, a magnetic field is formed by applying a current in the same direction as the sense current to the lower magnetoresistive thin films and the upper magnetoresistive thin films. 8. The method of manufacturing a magnetoresistive effect thin film magnetic head according to claim 7, wherein 11. A lower magnetoresistive thin film, an antiferromagnetic film,
After sequentially forming the upper magnetoresistive effect thin films in contact with each other, the lower magnetoresistive effect thin film and the upper magnetoresistive effect thin film are subjected to heat treatment while applying a current in the same direction as the sense current. 11. The pattern shape of the thin film, the antiferromagnetic film, and the upper magnetoresistive effect thin film is a strip shape having a length of a plurality of elements cut out in the longitudinal direction and wider than the element. Manufacturing method of magnetoresistive thin film magnetic head.