JPH10320718A - Magnetoresistive magnetic head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magneto-resistive effect magnetic head capable of applying a uniform bias magnetic field to a magneto-resistive effect layer without increasing impedance and improving a reproducing output by providing a magnetic layer magnetized vertically to a surface opposite to a magnetic recording medium, providing a non-magnetic insulation layer on it and further providing the magneto-resistive effect layer on it. SOLUTION: A magneto-resistive effect element 1 is in the state buried into a non- magnetic insulation body 5 of material excellent at a running characteristic since it is exposed on a surface opposite to the medium. The magnetic layer 11 is insulated by the non-magnetic insulation body 5, and since its upper surface is insulated by the non-magnetic insulation layer, a sense current doesn't flow through it. An MR head using this magneto-resistive effect element 1 causes a static magnetic connective action between the magneto-resistive effect layer 13 and the magnetic layer 11, and the magnetic stability of the magneto-resistive effect layer 13 is enhanced, and a Barkthausen noise is reduced. Then, the sense current is supplied to only the magneto- resistive effect layer 13, and here becomes a magnetosensitive part. Thus, thickness of a part contributing to a reproducing output in this MR head becomes only the thickness of the magneto-resistive effect layer 13 part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistance effect type magnetic head suitable for a hard disk drive or the like for detecting a reproduction signal by a magnetoresistance effect.

[0002]

2. Description of the Related Art In a magnetic recording device such as a hard disk device, further high-density recording is required in order to increase the capacity. Therefore, in recent years, in order to promote high-density recording, a magneto-resistive magnetic head (hereinafter, referred to as an MR head), which is a magnetic head suitable for narrowing tracks, has been adopted. This MR head detects a change in resistance as a reproduction output voltage by utilizing the fact that the resistivity of a magnetic thin film changes due to a magnetic field from a magnetic recording medium. Because of this principle, even when the medium is stopped, the medium shows an electric resistance value that is sensitive to magnetic flux, so that it is used as a read head of a hard disk or the like.

In an MR head, a magnetoresistive element (hereinafter, referred to as an MR element) is used for reproducing recorded magnetic information. In order to improve the output and nonlinearity of the MR element, it is necessary to apply a uniform and optimally large bias magnetic field.

The present inventor has proposed a magnetoresistive effect type magnetic head (hereinafter, referred to as a vertical MR head) in which the longitudinal direction of the MR head is arranged perpendicular to the surface facing the medium. doing. In this vertical MR head, in order to apply a bias magnetic field, a bias current line is arranged near the magnetoresistive layer, and a current is caused to flow through the line to apply a uniform bias magnetic field to the magnetoresistive layer. That is, a so-called bias application method using a bias current is used.

[0005]

The bias application method described above uses a series connection type bias current system in which an MR element and a bias current terminal are connected in series.
Therefore, by using the sense current, it is possible to automatically apply the bias magnetic field as well as to detect the reproduction output, which is the original purpose of use of the sense current, which is preferable in terms of efficiency. That is, the sense current can be used as the bias current.

However, when the sense current is used as the bias current as described above, there is a problem that the impedance increases because the MR element and the bias current terminal are connected in series.

Accordingly, the present invention has been proposed in view of such a conventional situation, and it is possible to apply a uniform bias magnetic field to the magnetoresistive layer without increasing the impedance, and to reproduce the data. It is an object of the present invention to provide a high-quality magnetoresistive head with improved output.

[0008]

According to the present invention, there is provided a magnetoresistive head having a magnetic layer magnetized in a direction substantially perpendicular to a surface facing a magnetic recording medium. A non-magnetic insulating layer formed on the layer; and a magneto-resistance effect layer formed on the non-magnetic insulating layer and exhibiting a magneto-resistance effect.

It is preferable that the magnetic layer has at least a soft magnetic film and an antiferromagnetic film. Note that the magnetic layer may include a hard magnetic film.

Further, on both sides of the magnetoresistive layer,
Preferably, a magnetic layer is provided, and more preferably, the magnetic layer has a hard magnetic film.

The magneto-resistance effect type magnetic head according to the present invention having the above-described structure has a magnetic layer magnetized in a direction substantially perpendicular to the surface facing the magnetic recording medium, and a magneto-resistance effect exhibiting the magneto-resistance effect. With the effect layer, a bias magnetic field can be applied to the magnetoresistive layer by a magnetic field generated from the magnetic layer. Therefore, since a bias applying method using a bias current is not used, an increase in impedance can be prevented, and a uniform bias magnetic field can be applied to the magnetoresistive layer.

Further, in the magnetoresistive head according to the present invention, the magnetic layer has at least a soft magnetic film and an antiferromagnetic film, so that the antiferromagnetic film has a magnetization direction of the soft magnetic film. Is fixed. Thus, it is possible to prevent the magnetization direction of the soft magnetic film from rotating due to the influence of the magnetic field generated by the sense current used for obtaining the reproduction output.

In the magnetoresistive head according to the present invention, the magnetic layers are disposed on both sides of the magnetoresistive layer, so that the demagnetizing field generated at the end of the magnetoresistive layer is canceled out. The magnetization of the resistance effect layer can be further stabilized.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

As shown in FIG. 1, the MR head basically has a structure in which electrodes 2 are attached to both ends of a magnetoresistive element 1 having a magnetoresistive layer whose resistivity changes according to the magnitude of a magnetic field. Is done. By supplying a sense current to the magnetoresistive element 1 from the electrodes 2 at both ends, a change in resistance of the magnetoresistive element 1 due to a signal magnetic field from the magnetic recording medium is detected, and based on the change in resistance. Get playback output. In such an MR head,
The reproduction output does not depend on the medium speed, and a high reproduction output can be obtained even when the medium speed is low.

A magnetoresistive head according to the present invention is an MR head having a magnetoresistive element 1 having a magnetoresistive layer. As shown in FIG. 2, a lower shield 3 and a lower shield 3 are provided. The lower gap layer 4 formed thereon, the magnetoresistive element 1 and the non-magnetic insulating layer 5 formed on the lower gap layer 4, and the portions other than the front end portion 1 a and the rear end portion 1 b on the magnetoresistive effect element 1. Protective layer 6 formed on part
A sense current conductor layer 7 formed on the non-magnetic insulating layer 5 from the rear end portion 1b of the magnetoresistive element 1; and a non-magnetic insulating layer formed on the magnetoresistive effect element 1 and the sense current conductor layer 7. Layer 8, magnetoresistive element 1, and tip 1a
At the tip 1 of the magnetoresistive element 1
The upper gap layer 9 is formed over the non-magnetic insulating layer 8 from above a, and the upper shield 10 is formed on the upper gap layer 9.

In the above MR head, the lower shield 3
The upper gap layer 10 is made of a magnetic material, the lower gap layer 4 is made of a non-magnetic insulating material, and the upper gap layer 10 is made of a non-magnetic material that is electrically good. The lower shield 3, the upper shield 10, the lower gap layer 4, and the upper gap layer 9 function so as to prevent a magnetic field outside the reproduction target from the signal magnetic field from the magnetic recording medium from being drawn into the magnetoresistive element 1. . That is, since the lower shield 3 and the upper shield 10 are arranged above and below the magnetoresistive element 1 via the lower gap layer 4 and the upper gap layer 9, the signal magnetic field from the magnetic recording medium other than the target to be reproduced is included. Is guided to the lower shield 3 and the upper shield 10, and only the magnetic field to be reproduced is drawn into the magnetoresistive element 1.

On the other hand, the conductor layer 7 for sense current and the upper gap layer 9 become a pair of electrodes respectively connected to both ends of the magnetoresistive element 1, and function to supply a sense current to the magnetoresistive element 1. . In other words, the magnetoresistive element 1 has the sensing current conductor layer 7 at the rear end 1b.
And is electrically connected to the upper gap layer 9 at the tip 1a. Then, when a signal magnetic field is detected from the magnetic recording medium, a sense current flows through the magnetoresistive element 1 via the signal magnetic field.

Here, as will be described later, the magnetoresistive element 1 is formed by sequentially laminating a magnetic layer, a non-magnetic insulating layer, and a magnetoresistive layer.

In the MR head thus configured, the conductor layer 7 for sense current and the upper gap layer 9 form a pair of electrodes, and this sense current flows through the magnetoresistive element 1. The MR head detects the change in resistance as a reproduction output by utilizing the fact that the resistivity in the magnetoresistive layer in the magnetoresistive element 1 changes due to the magnetic field from the magnetic recording medium.

FIG. 3 shows the MR head as viewed from the side facing the magnetic recording medium as indicated by arrow Z in FIG. As shown in FIG. 3, the magnetoresistive element 1 has a magnetic layer 11, a non-magnetic insulating layer 12, a magnetoresistive layer 13
Are laminated.

The magnetoresistive element 1 has a non-magnetic insulator 5 on both sides, and is in a state of being embedded in the non-magnetic insulator 5. Here, since the non-magnetic insulator 5 is exposed on the surface facing the medium, it is preferable that the non-magnetic insulator 5 be made of a material having excellent running characteristics.
Materials such as ₂ O ₃ , SiO ₂ , SiN _x (Si ₃ N ₄ etc.) are suitable.

The magnetoresistive element 1 and the electrodes are connected at both ends of the upper surface of the magnetoresistive element 1. That is, as shown in FIG. 2, at the front end 1a of the magnetoresistive element 1, the upper surface of the magnetoresistive layer 13 is electrically connected to the upper gap layer 9, and the rear end of the magnetoresistive element 1 is connected. In the portion 1b, the upper surface of the magnetoresistive layer 13 and the conductor layer 7 for sense current are electrically connected. Here, as shown in FIG. 3, the magnetic layer 11 is insulated by the non-magnetic insulator 5 and the upper surface is insulated by the non-magnetic insulating layer 12, so that no sense current flows.

In the MR head using such a magneto-resistance effect element 1, the magneto-resistance effect layer 13 and the magnetic layer 11
A magneto-static coupling effect occurs between the magnetoresistive effect layer 1
3 increases the magnetic stability and reduces Barkhausen noise.

In this MR head, the magnetoresistive layer 13
Only the magnetoresistive effect layer 13 functions as a magnetic sensing part because a sense current is supplied to only the magnetoresistive layer. Therefore, in this MR head, the thickness of the portion contributing to the reproduction output is only the thickness of the magnetoresistive layer 13. for that reason,
In this MR head, the thickness of the portion contributing to the reproduction output can be reduced by half as compared with the MR head in which the sense current flows also in the magnetic layer 11, and a high reproduction output can be obtained with this MR head. It is.

In particular, as shown in FIG. 3, the magnetic layer 11 used in the magnetoresistive element 1 to which the present invention is applied is substantially perpendicular to the surface 14 facing the magnetic recording medium. Is magnetized by applying a magnetic field. The magnetization direction may be a direction directly opposite to the direction shown in FIG. 3, that is, a direction substantially perpendicular to the inside of the MR head from the surface opposite to the surface facing the magnetic recording medium. Here, the magnetic layer 11 is magnetostatically coupled to the magnetoresistive layer 13,
This contributes to improving the magnetic stability of the magnetoresistive layer 13.

The magnetoresistive layer 13 is made of, for example, N
It may be a single-layer film made of iFe or the like and having a magnetoresistance effect, or may be NiF on a base film made of Ta or the like.
e and the like may be laminated.

Next, referring to FIG.
Another example of the magneto-resistance effect element in the R head will be described.

As shown in FIG. 4, in the magnetoresistive element 1 of the MR head to which the present invention is applied, the magnetic layer 11 has a soft magnetic film 15 and an antiferromagnetic film 16. Antiferromagnetic film 16, nonmagnetic insulating layer 17, and magnetoresistive layer 18
Are preferably sequentially laminated. In addition,
The soft magnetic film 15 and the antiferromagnetic film 16 may not be formed in the above order, that is, the soft magnetic film 15 may be formed on the antiferromagnetic film 16.

Here, the soft magnetic film 15 is magnetized by applying a magnetic field in a direction 14 in the figure which is substantially perpendicular to the surface facing the magnetic recording medium. The soft magnetic film 15 may be made of Co, CoFe, NiFe, NiFe-X.
(X = Ta, Cr, Nb) and the like.

On the other hand, the antiferromagnetic film 16 can prevent the magnetization direction of the soft magnetic film 15 from being rotated by the influence of the magnetic field generated by the current flowing through the magnetoresistive effect layer 18, and as a result, The magnetization direction of the soft magnetic film 15 is fixed and stabilized. The material of the antiferromagnetic film 16 is FeM
n, IrMn, CrMnPt, NiO and the like.
In particular, when the positions of the soft magnetic film 15 and the antiferromagnetic film 16 are opposite, that is, when the soft magnetic film 15 is formed on the antiferromagnetic film 16, NiO is used as the material of the antiferromagnetic film 16. preferable.

Referring to FIG. 5, another example of the magnetoresistive element 1 in the MR head to which the present invention is applied will be described.

In the magnetoresistive element 1 of the MR head to which the present invention is applied, the magnetic layer 11 comprises a soft magnetic film 19 and an antiferromagnetic film 20, as in the magnetoresistive effect element 1 shown in FIG.
A soft magnetic film 19, an antiferromagnetic film 20, a non-magnetic insulating layer 21, and a magnetoresistive layer 22 are sequentially laminated, and, as shown in FIG. It is more preferable that the magnetic layer 23 is provided.

The magnetic layer 23 can stabilize the magnetization direction of the magneto-resistance effect film 22 by canceling out the demagnetizing field generated at the end of the magneto-resistance effect layer 22. Particularly, as the magnetic layer 23 of the magnetoresistive element 1 in the MR head to which the present invention is applied, for example, a hard magnetic layer made of a hard magnetic material such as CoPt, CoPtCr or CoNi is preferable. Moreover, a hard magnetic layer having a resistance ratio of about 1 × 10 ⁶ or more to the magnetoresistive film 22 is more preferable. Therefore, it is possible to prevent the sense current supplied to the magnetoresistive layer 22 from being lost from the magnetic layer 23.

It should be noted that even if the magnetic layer 23 is not formed on the entire surface on both sides of the magnetoresistive element 1 as shown in FIG. 5, the magnetic direction of the magnetoresistive layer 22 is stabilized. It is sufficient if it is formed, that is, as long as it is formed on at least both side surfaces of the magnetoresistive layer 22 as shown in FIG. At this time, the soft magnetic film 19 and the antiferromagnetic film 2
0 and both sides of the non-magnetic insulating layer 21
It is good to be.

In the MR element 1 of the MR head to which the present invention is applied, as shown in FIG. 7, a hard magnetic layer 25, a nonmagnetic insulating layer 26, and a magnetoresistive layer 27 are sequentially laminated. May be. At this time, the material used for the hard magnetic layer 26 is the same as that of the hard magnetic layer 23 described above.

The magneto-resistive element 1 in the magneto-resistive magnetic head according to the present invention configured as described above.
Is applied with a bias magnetic field as described below. Here, as the magnetoresistive element 1, a soft magnetic film 19, an antiferromagnetic film 20, an insulating film 21, and a magnetoresistive film 22 as shown in FIG. The description will be given using a case where the magnetic layer 23 having a magnetic film is formed.

In the soft magnetic film 19, the magnetization direction of the soft magnetic film 19 is fixed by the annealed antiferromagnetic film 20. Here, the magnetization direction of the soft magnetic film 19 is
The direction is substantially perpendicular to the surface facing the magnetic recording medium. For example, as shown in FIG. 8, a substantially vertical direction toward the surface facing the magnetic recording medium from the interior MR heads, that is, A ₁ direction in the drawing. The magnetic field from the soft magnetic film 19 is magnetized in the A ₁ direction in the drawing, in FIG on the magnetoresistive layer 22 A
Applies a magnetic field in _two directions. Then, the magnetoresistive layer 22
Is magnetized in the direction a in the figure when a bias magnetic field is applied.

The magnetic layer 23 is magnetized so that, for example, the magnetization direction is parallel to the surface facing the magnetic recording medium, that is, the direction B in the drawing. Then, the magnetoresistive effect layer 22 is oriented in the same direction as the magnetic layer 23,
A magnetic field is applied in the direction to be magnetized.

As described above, the magnetization in the directions a and b in the figure finally causes the magnetoresistive
A bias magnetic field having a directional magnetization direction will be applied.

That is, the magnetoresistance effect element 1 used in the magnetoresistance effect type magnetic head to which the present invention is applied is affected by the magnetic field generated in the soft magnetic film 19 magnetized in the above-described predetermined direction, and A linear bias magnetic field can be applied to layer 23. Moreover, by arranging the magnetic layers 23 magnetized in a predetermined magnetization direction on both side surfaces of the magnetoresistive element 1, the magnetization direction of the magnetoresistive layer 23 by the linear bias magnetic field is controlled to a desired direction, It is possible to stabilize.

As shown in FIGS. 3, 4 and 7,
When the magnetic layer 23 is not formed, only the magnetization in the direction b in the drawing disappears, and the application of the bias magnetic field is performed in the same manner as described above.

[0043]

As described in detail above, the magneto-resistance effect type magnetic head according to the present invention has a magnetic layer magnetized in a direction substantially perpendicular to the surface facing the magnetic recording medium, and a magnetic layer formed on the magnetic layer. And a magnetoresistive layer formed on the nonmagnetic insulating layer and exhibiting a magnetoresistive effect.

As a result, since a bias applying method using a bias current is not used, a uniform bias magnetic field can be applied to the magnetoresistive layer without increasing the impedance, and the reproduction output can be improved to achieve a high output. Can be quality.

In the magneto-resistance effect type magnetic head according to the present invention, the magnetic layer is composed of the soft magnetic film and the antiferromagnetic film, so that the antiferromagnetic film fixes the magnetization direction of the soft magnetic film. . Therefore, the magnetization direction of the soft magnetic film can be prevented from rotating due to the magnetic field generated by the sense current, and the magnetization direction of the soft magnetic film can be stabilized. A bias magnetic field can be applied.

Further, in the magnetoresistive head according to the present invention, by arranging the magnetic layers on both side surfaces of the magnetoresistive layer, the magnetic layer prevents the loss of the sense current and the end of the magnetoresistive layer. By canceling the demagnetizing field generated in the part, the magnetization of the magnetoresistive layer can be further stabilized,
The reproduction output can be improved. Here, in particular, by using a magnetic layer having a hard magnetic film as the magnetic layer disposed on both side surfaces of the magnetoresistive layer, the reproduction output characteristics can be further improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an example of a basic configuration of a magneto-resistance effect type magnetic head.

FIG. 2 is a sectional view of a main part showing an example of a magnetoresistive head.

FIG. 3 is a main part front view of an example of a magnetoresistive magnetic head to which the present invention is applied, viewed from a surface facing a medium.

FIG. 4 is a fragmentary front view of another example of a magnetoresistive head to which the present invention is applied, viewed from a surface facing a medium.

FIG. 5 is a main part front view of another example of the magnetoresistive head to which the present invention is applied, viewed from a surface facing a medium.

FIG. 6 is a fragmentary front view of another example of the magnetoresistive head according to the present invention, as viewed from a surface facing a medium.

FIG. 7 is a main part front view of another example of the magnetoresistive head according to the present invention, viewed from a surface facing a medium.

FIG. 8 is a perspective view showing an example of a magnetoresistive head according to the present invention.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 magnetoresistive element, 7 conductive layer for sense current, 1
1,23 magnetic layer, 12,17,21,26 nonmagnetic insulating layer, 13,18,22,27 magnetoresistive layer, 15,19
Soft magnetic film, 25 Hard magnetic layer, 16,20 Antiferromagnetic film

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takuji Shibata 6-7-35 Kita Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Hiroaki Narusawa 6-7-1 Kita Shinagawa, Shinagawa-ku, Tokyo No. 35 Sony Corporation

Claims (5)

[Claims] A magnetic layer magnetized in a direction substantially perpendicular to a surface facing a magnetic recording medium; a nonmagnetic insulating layer formed on the magnetic layer; and a nonmagnetic insulating layer formed on the nonmagnetic insulating layer. And a magnetoresistive layer exhibiting a magnetoresistive effect. 2. The magnetic layer according to claim 1, wherein the magnetic layer has at least an antiferromagnetic film and a soft magnetic film magnetized in a direction substantially perpendicular to a surface facing the magnetic recording medium. Magnetoresistive magnetic head. 3. The magnetoresistive head according to claim 1, wherein said magnetic layer has at least a hard magnetic film. 4. The magnetoresistive effect type magnetic device according to claim 1, wherein said magnetoresistive effect layer has a substantially rectangular shape, and magnetic layers are arranged on both side surfaces of said magnetoresistive effect layer. head. 5. The magnetoresistive head according to claim 4, wherein the magnetic layers disposed on both sides of the magnetoresistive layer have at least a hard magnetic film.