JP2001148104A - Magnetoresistive magnetic head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the output of a magnetoresistive element from being deteriorated when the track width is narrowed in this magnetoresistive magnetic head, where the direction of a sense current flowing in the magnetoresistive element is made nearly perpendicular, with respect to the intra-surface direction of a magnetic recording medium. SOLUTION: This magnetoresistive element is constituted, so that at least a magnetization liberating layer for changing the magnetization direction according to an outside magnetic field and a magnetization fixing layer for fixing the magnetization direction to a prescribed direction are laminated, while going through the intermediary of a nonmagnetic layer and hard magnetic films are disposed on the both sides of the magnetization liberating layer, while interposing soft magnetic films of electric insulation property in this magnetoresistive magnetic head where the direction of the sense current flowing in the magnetoresistive element is made nearly perpendicular with respect to the intra-surface direction of the magnetic recording medium.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive head in which the direction of a sense current flowing in a magnetoresistive element is substantially perpendicular to the in-plane direction of a magnetic recording medium.

[0002]

2. Description of the Related Art A magnetoresistive element is an element whose resistance value changes according to the magnitude of an external magnetic field, and is used, for example, as a magneto-sensitive element for detecting a magnetic signal from a magnetic recording medium in a magnetic head. A magnetic head including the magnetoresistive element is generally called a magnetoresistive magnetic head (hereinafter, referred to as an MR head).

Examples of the magnetoresistive element include a magnetoresistive element using an anisotropic magnetoresistive effect and a giant magnetoresistive element using a spin valve film.

In addition, the MR head has a vertical MR head in which the direction of a sense current flowing through the magnetoresistive element is perpendicular to the in-plane direction of the magnetic recording medium, or the in-plane direction of the magnetic recording medium. There is a horizontal MR head that is substantially parallel. Among them, the vertical MR head has an advantage that its reproduction output does not depend on the track width.

Here, an example of such a vertical MR head is shown in FIG.

In this MR head, a non-magnetic layer 102 includes a magnetization free layer 100 whose magnetization direction is changed in accordance with an external magnetic field, and a magnetization fixed layer 101 whose magnetization is fixed in a predetermined direction.
And a magnetoresistive effect element 103 that is laminated through the intermediary.

The magnetoresistive element 103 is, for example, a giant magnetoresistive element using a spin valve film.
The magnetization free layer 100 is made of a soft magnetic film having a high magnetic permeability such as, for example, NiFe or CoFe.
However, the magnetization direction is fixed in a predetermined direction by an exchange coupling magnetic field acting between an antiferromagnetic film such as IrMn, CoFe, and Co, for example, NiFe, C
The nonmagnetic layer 102 is made of a soft magnetic film having a high magnetic permeability such as oFe or Co, and the nonmagnetic layer 102 is made of a nonmagnetic film such as Au, Ag, or Cu.

A sense current is supplied to the magnetoresistive element 103 at the front and rear ends thereof in a direction substantially perpendicular to the in-plane direction of the magnetic recording medium. Electrode 104 and rear electrode 105 for
Are disposed so as to contact the magnetization free layer 100.

A pair of hard magnetic films 106 for applying a bias magnetic field to the magnetization free layer 100 are provided on both sides of the magnetoresistance effect element 103 in order to stabilize the magnetic domains of the magnetization free layer 100. ing. This hard magnetic film 106
Is formed of a hard magnetic material such as Coγ-Fe ₂ O ₃ .

Although FIG. 12 shows only the magnetoresistive element 103 constituting the MR head, the magnetoresistive element 103 serving as the magnetic sensing portion is made of a non-magnetic material in the MR head. The inserted non-shield type MR head or the magnetoresistive element 1 for improving the reproduction frequency characteristic of the non-shield type MR head
Shielded MR 03 magnetically shielded with soft magnetic material
A magnetic flux is led to the magnetoresistive element 103 for improving the head or wear resistance, etc.
A non-exposed yoke type MR head 03 is used.

The MR head is a so-called thin-film magnetic head in which each component is formed on a substrate by a thin-film forming process.
0, a magnetization fixed layer 101, a nonmagnetic layer 102, and the like, as well as an underlayer, a protective layer, and the like.

In the vertical MR head configured as described above, when reproducing the information signal from the magnetic recording medium, the magnetic recording medium is caused to run so as to face the magnetoresistive element 103, To detect the signal magnetic field from the magnetic recording medium. Here, the magnetoresistance effect element 1
In the detection of the signal magnetic field by the reference numeral 03, a sense current is supplied to the magnetoresistive element 103 through the front electrode 104 and the rear electrode 105 in a direction substantially perpendicular to the in-plane direction of the magnetic recording medium. This is performed by detecting a voltage change of

In this MR head, a portion sandwiched between the pair of hard magnetic films 106 is the magnetoresistive element 10.
The width of this portion is the reproduction track width W of the MR head.

[0014]

By the way, in the above-described vertical MR head, in the magnetoresistive element 103,
In order to stabilize the magnetic domains of the magnetization free layer 100, it is necessary that the bias magnetic field applied from the hard magnetic film 106 be appropriately applied to the magnetization free layer 100.

That is, in this vertical MR head, the thickness of the magnetization free layer 100 in the magnetoresistive element 103 is t, the saturation magnetization of the magnetization free layer 100 is M _S ,
The thickness of the hard magnetic film 106 is set to δ ^PM ,
When residual magnetization was an M _r ^PM, such that ^{_{M r PM δ PM ≧ 2M S}} t designs it has been made. Note that this is a horizontal M
The same applies to the case where an R head is used.

However, in this vertical MR head,
As described above, even though the output of the magnetoresistive element 103 is not dependent on the track width, when the reproducing track width W is reduced in response to the increase in recording density, the magnetoresistive element 103 In some cases, the output was greatly reduced.

Here, in the vertical MR head, the output of the magnetoresistive element 103 is proportional to the magnetic flux penetration length. The magnetic flux penetration length is one of the magnetic permeability of the magnetization free layer 100.
/ 2 power. The magnetic permeability of the magnetization free layer 100 is inversely proportional to the sum of the bias magnetic field applied from the hard magnetic film 106 and the anisotropic magnetic field of the magnetization free layer 100. Therefore, the output of the magnetoresistive element 103 is determined by the bias magnetic field applied from the hard magnetic film 106 and the magnetization free layer 10.
It will be inversely proportional to the 1/2 power of the sum of 0 and the anisotropic magnetic field.

FIG. 13 is a graph showing the relationship between the output of the magnetoresistive element 103 when the reproduction track width W of the vertical MR head is changed. Note that here, MR
The reproducing gap length of the head is set to 0.07 μm, and the sense current supplied to the magnetoresistive element 103 is fixed.

As shown in FIG. 13, in the MR head, as the reproduction track width W increases, the output of the magnetoresistive element 103 becomes constant without depending on the reproduction track width W. . However,
In this MR head, when the reproduction track width W becomes narrow,
It can be seen that the output of the magnetoresistive element 103 decreases. This is because the average of the bias magnetic field from the hard magnetic film 106 applied to the magnetization free layer 100 increases as the reproduction track width W decreases.

Next, the reproduction track width W is set to, for example, 0.2
FIG. 14 is a graph showing the distribution of the bias magnetic field from the hard magnetic film 106 applied to the magnetization free layer 100 in the track width direction when the width is reduced to μm. FIG. 15 is a graph showing the distribution of the magnetic permeability in the track width direction.

As shown in FIG. 14, when the reproduction track width W is reduced, the bias magnetic field applied from the hard magnetic film 106 to the magnetization free layer 100 is relatively stable at the central portion. On the other hand, it can be seen that it is larger at both ends. Therefore, in the MR head, the magnetization free layer 100
The average of the bias magnetic field applied from the hard magnetic film 106 increases, and the output of the magnetoresistive element 103 decreases.

As shown in FIG. 15, when the reproduction track width W is narrowed, the magnetic permeability of the magnetization free layer 100 has a peak at the center and decreases toward both ends in the track width direction. It can be seen that it shows a uniform distribution. This decrease in the magnetic permeability of the magnetization free layer 100 is a direct cause of reducing the output of the magnetoresistive element 103 from the relationship between the magnetic permeability of the magnetization free layer 100 and the output of the magnetoresistive element 103. Further, in this MR head, since the distribution of the magnetic permeability of the magnetization free layer 100 in the track width direction of the magnetoresistive element 103 is not uniform, there is a possibility that off-track characteristics may be reduced.

As described above, in the conventional vertical MR head,
When the reproduction track width W is reduced in response to the increase in the recording density, the influence of the bias magnetic field from the hard magnetic film 106 applied to the magnetization free layer 100 becomes too large. Is difficult to stabilize, and as a result, the output of the magnetoresistive element 103 may be greatly reduced.

Therefore, the present invention has been proposed in view of such a conventional situation, and the direction of the sense current flowing through the magnetoresistive effect element is substantially perpendicular to the in-plane direction of the magnetic recording medium. It is an object of the present invention to provide a magnetoresistive head that prevents a decrease in the output of the magnetoresistive element when the track width is reduced and is capable of responding to a higher recording density. .

[0025]

According to the present invention, there is provided a magneto-resistance effect type magnetic head in which the direction of a sense current flowing through a magneto-resistance effect element is substantially perpendicular to an in-plane direction of a magnetic recording medium. In the magneto-resistance effect type magnetic head, the magneto-resistance effect element includes at least a magnetization free layer that changes a magnetization direction according to an external magnetic field, and a magnetization fixed layer in which magnetization is fixed in a predetermined direction. And a hard magnetic film is disposed on both sides of the magnetization free layer via an insulating soft magnetic film.

As described above, in the magneto-resistance effect type magnetic head according to the present invention, since the hard magnetic film is provided on both sides of the magnetization free layer via the insulating soft magnetic film, Is applied to the magnetization free layer via the insulating soft magnetic film. Thereby, in this magnetoresistive head, even when the track width is reduced, the magnetic domains of the magnetization free layer can be stabilized,
It is possible to prevent the output of the magnetoresistive element from lowering.

[0027]

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

A magnetoresistive head (hereinafter referred to as an MR head) to which the present invention is applied has a longitudinal direction in which the direction of a sense current flowing through the magnetoresistive element is substantially perpendicular to the in-plane direction of the magnetic recording medium. Type MR head.

As shown in FIG. 1, the MR head has a magnetization free layer 1 that changes the magnetization direction according to an external magnetic field,
The magneto-resistance effect element 4 includes a magnetization fixed layer 2 whose magnetization is fixed in a predetermined direction and a magnetic resistance effect element 4 that is stacked with a non-magnetic layer 3 interposed therebetween.

The magnetoresistive element 4 is a giant magnetoresistive element using, for example, a spin valve film, and the magnetization free layer 1 is made of a soft magnetic film such as NiFe or CoFe having a high magnetic permeability. When the fixed layer 2 is, for example, I
The magnetization is fixed in a predetermined direction by an exchange coupling magnetic field acting between an antiferromagnetic film such as rMn, CoFe, and Co, and has a high magnetic permeability such as NiFe, CoFe, and Co. The nonmagnetic layer 3 is made of a soft magnetic film.
It is made of a non-magnetic film such as u, Ag, and Cu.

A sense current is supplied to the magnetoresistive element 4 at the front and rear ends thereof in a direction substantially perpendicular to the in-plane direction of the magnetic recording medium. Electrode 5 and rear electrode 6 for the
It is arranged so as to abut. In the MR head, the end face of the magnetoresistive element 4 on the side where the tip electrode 5 is provided is a medium facing surface facing the magnetic recording medium.

In the magnetoresistive effect element 4, hard magnetic films 8 are provided at both ends of the magnetization free layer 1 as viewed from the medium facing surface side via an insulating soft magnetic film 7.

The insulating soft magnetic film 7 has a thickness of at least 20 μm.
It is formed of a soft magnetic material having a specific resistance of Ωcm or more. Specifically, as the insulating soft magnetic film 7, N 2
i, Fe, or a magnetic material containing any of Co elements, and these magnetic materials and Ti, V, Cr, Cu, Zr, Nb, Mo, and R
Alloys containing any one of the elements u, Rh, Pd, Hf, Ta, W, Fr, Pt, and Au, as well as oxides and nitrides thereof, may be mentioned. For example, as such an insulating soft magnetic film 7, NiFe, NiFeCo, CoTaZn, or the like can be given. Further, as the insulating soft magnetic film 7,
A metal containing any of Ni, Fe, and Co elements, MgO,
A granular magnetic thin film with a non-metal containing any of Al2O3, SiO2, an oxide of Ta, and an oxide of Ti can be given.

When the insulating soft magnetic film 7 has a specific resistance of at least 20 μmΩcm, it is possible to prevent a sense current from flowing from the magnetoresistive effect element 4 into the insulating soft magnetic film 7.

On the other hand, the hard magnetic film 8 is for applying a bias magnetic field to the magnetization free layer 1 in order to stabilize the magnetic domain of the magnetization free layer 1. For example, CoCrPt,
It is formed of a hard magnetic material such as CoPt, CoNiPt, and Coγ-Fe ₂ O ₃ .

FIG. 1 shows only the magnetoresistive element 4 constituting the MR head.
As the R head, a non-shield type MR head in which the magneto-resistance effect element 4 serving as a magnetic sensing part is sandwiched by a non-magnetic material, or a magneto-resistance effect element for improving the reproduction frequency characteristic of the non-shield type MR head 4 is a shield type MR head magnetically shielded with a soft magnetic material, or a yoke type in which a magnetic flux is guided to the magnetoresistive effect element 4 for improving wear resistance and the like, and the magnetoresistive effect element 4 is not exposed. An MR head is exemplified.

This MR head is a so-called thin-film magnetic head in which each constituent element is laminated on a substrate by a thin-film forming step, and includes the above-described magnetization free layer 1, magnetization fixed layer 2, non-magnetic layer 3 In addition to the above, an underlayer, a protective layer and the like are provided.

In the MR head configured as described above,
When reproducing an information signal from the magnetic recording medium, the magnetic recording medium is caused to run so as to face the magnetoresistive element 4, and the magnetoresistive element 4 detects a signal magnetic field from the magnetic recording medium. Here, the detection of the signal magnetic field by the magnetoresistive effect element 4 is performed by detecting the sense current in the direction substantially perpendicular to the in-plane direction of the magnetic recording medium through the front end electrode 5 and the rear end electrode 6. Is supplied, and the voltage change of the sense current is detected. In this MR head, the interval between the magnetoresistive elements 4 in the portion sandwiched between the insulating soft magnetic films 7 is set to the reproduction track width W.

In the MR head, the magnetization of the insulating soft magnetic film 7 is fixed in a predetermined direction by the exchange coupling magnetic field (bias magnetic field) acting between the magnetoresistive effect element 4 and the hard magnetic film 8. The magnetization of the magnetization fixed layer 2 is fixed in a predetermined direction by an exchange coupling magnetic field acting between the insulating soft magnetic film 7 and the magnetization fixed in the predetermined direction. That is, in the magnetoresistive effect element 4, the bias magnetic field from the hard magnetic film 8 is applied to the magnetization free layer 1 via the insulating soft magnetic film 7.

In this case, in the magnetoresistive element 4, the exchange coupling constant is set to 1 × 10 ⁻⁸ erg / cm or more because the insulating soft magnetic film 7 and the magnetization free layer 1 are ferromagnetically coupled. preferable. In the magnetoresistive element 4, the width W of the soft magnetic insulating film is increased in order to increase the magnetic permeability of the magnetization free layer 1.
^B is preferably set to 10 nm or more.

In the magnetoresistive effect element 4, similarly to the above-described conventional MR head, the thickness of the magnetization free layer 1 is represented by t, the saturation magnetization of the magnetization free layer 1 is represented by M _S , and the hard magnetic film 8 is formed. Δ ^PM and the residual magnetization of the hard magnetic film 8 is represented by M _r
When the ^PM, it is preferable that the ^{_{M r PM δ PM ≧ 2M S}} t. Furthermore, the magnetoresistive element 4, in order to avoid magnetic domains are formed in the boundary portion between the magnetization free layer 1 and the insulating soft magnetic film 7, a saturation magnetization of the insulating soft magnetic film 7 and M _S ^B When the thickness of the insulating soft magnetic film 7 is t ^B , M _S
It is preferred that the ^B t ^{B ≒} M _S t.

In the magnetoresistive effect element 4, since the bias magnetic field from the hard magnetic film 8 is applied to the magnetization free layer 1 via the insulating soft magnetic film 7, the anisotropic soft magnetic film 7 It is preferable that the coercive magnetic field or coercive force be 1000 Oe or less. Similarly, in the magnetoresistive effect element 4, since the bias magnetic field from the hard magnetic film 8 is applied to the magnetization free layer 1 via the insulating soft magnetic film 7, the anisotropic magnetic field of the hard magnetic film 8 It is preferable that the magnetic force be 100 Oe or more.

FIG. 2 is a graph showing the relationship between the output of the magnetoresistive element 4 when the reproduction track width W of the MR head is changed. Here, the read gap length of the MR head and 0.07 .mu.m, the width W ^B of the insulating soft magnetic film 7 and 200 nm, the sense current supplied to the magnetoresistive element 4 is constant. The output of the magnetoresistive element 4 of the MR head to which the present invention is applied is shown by a thick line, and for comparison, the output of the magnetoresistive element 103 of the conventional MR head shown in FIG. I do.

As is apparent from FIG. 2, the output of the magnetoresistive element 103 decreases as the reproduction track width W decreases in the conventional MR head, whereas in the MR head to which the present invention is applied. It can be seen that the output of the magnetoresistive element 4 does not decrease even when the reproduction track width W is reduced. That is, the MR to which the present invention is applied
It can be seen that in the head, the output of the magnetoresistive element 4 does not depend on the reproduction track width W.

Next, the reproduction track width W is set to, for example, 0.2
The insulating soft magnetic film 7 is formed on the magnetization free layer 1 when the thickness is reduced to μm.
FIG. 3 is a graph showing the distribution in the track width direction of the bias magnetic field applied from the hard magnetic film 8 through the hard magnetic film 8,
FIG. 4 is a graph showing the distribution of the magnetic permeability of the magnetization free layer 1 to which the bias magnetic field is applied in the track width direction.

As shown in FIG. 3, in this MR head,
Even when the reproduction track width W is reduced, the hard magnetic film 8 applied to the magnetization free layer 1 via the insulating soft magnetic film 7
It can be seen that the bias magnetic field is low and stable over the entire area in the track width direction.

Further, as shown in FIG. 4, in this MR head, even when the reproduction track width W is narrowed, the magnetic permeability of the magnetization free layer 1 to which the bias magnetic field is applied is reduced.
It can be seen that the distribution is high and uniform over the entire area in the track width direction.

As described above, in the MR head to which the present invention is applied, even when the reproduction track width W is narrowed, the output of the magnetoresistive effect element 4 does not decrease, and the recording density can be increased. It is possible.

Next, a specific example of an MR head to which the present invention is applied is shown in FIG. FIG. 5 is an end view of the MR head viewed from the medium facing surface side.

This MR head has a structure in which each constituent element is laminated on a substantially flat plate-like substrate made of a hard material such as Al ₂ O ₃ —TiC or various ceramics by a thin film forming process. It is used as a read-only magnetic head that reads a magnetic signal recorded on a magnetic recording medium.

This MR head is a vertical MR head in which the direction of the sense current flowing through the magnetoresistive element is substantially perpendicular to the in-plane direction of the magnetic recording medium. Electrode 5 for supplying
And a rear end electrode 6 (not shown in FIG. 5).

The MR head is a so-called shield type MR head, and includes a magnetoresistive element 4 and hard magnetic layers disposed on both sides of the magnetoresistive element 4 with insulating soft magnetic films 7 interposed therebetween. And a film 8 sandwiched by a lower shield layer 9 and an upper shield layer 10 with a lower gap layer 11 and an upper gap layer 12 interposed therebetween.

The magnetoresistive element 4 is a giant magnetoresistive element using a spin valve film. For example, a Ta layer 13 having a thickness of about 5 nm as a lower layer, and a NiFe layer having a thickness of about 5 nm as a magnetization free layer 1. 14 and about 5 nm thick Co
An Fe layer 15, a Cu layer 16 having a thickness of about 3 nm as the nonmagnetic layer 3, and a 2.5 μm thick CoFe layer as the magnetization fixed layer 2.
The layer 17 and the InMn layer 18 having a thickness of 6 μm, and a Ta layer 19 having a thickness of about 5 nm as an upper layer are formed in this order. The material of each layer constituting the magnetoresistive effect element 4 and the film thickness thereof are not limited to the above examples. An appropriate material is selected according to the purpose of use of the MR head and the like. Should be set to.

The insulating soft magnetic film 7 is made of, for example, NiFeCo.
And formed on both sides of the magnetization free layer 1 on the Ta layer 13 so as to reach the NiFe layer 14 and the CoFe layer 15 constituting the magnetization free layer 1.

The hard magnetic film 8 is made of, for example, Coγ-Fe ₂ O ₃ , and is formed on both sides of the insulating soft magnetic film 7 on the lower gap layer 11 so that the side portions have a gentle taper shape. .

In this MR head, the side surface of the magnetoresistive effect element 4 also has a gently tapered shape. The insulating soft magnetic film 7 is in contact between the magnetoresistive element 4 and the hard magnetic film 8 on the tapered side surface between the magnetoresistive element 4 and the hard magnetic film 8. It is formed as follows.

Thus, in the MR head, the magnetic coupling between the magnetoresistive effect element 4 and the hard magnetic film 8 and the insulating soft magnetic film 7 can be improved. Note that this MR
The head gap between the magnetoresistive element 4 and the hard magnetic film 8 are the width W ^B of the insulating soft magnetic film 7, where,
The width W ^B of the insulating soft magnetic film 7 was set to 200 nm.

Lower shield layer 9 and upper shield layer 10
Is made of a soft magnetic film such as Sendust. The lower shield layer 9 and the upper shield layer 10 function to prevent a magnetic field that is not to be reproduced out of the signal magnetic field from the magnetic recording medium from being drawn into the magnetoresistive element 4. That is, in the MR head, the signal magnetic field outside the reproduction target for the magnetoresistive element 4 is guided to the lower shield layer 9 and the upper shield layer 10, and only the signal magnetic field for the reproduction is guided to the magnetoresistive element 4. . Thereby, in the MR head, the frequency characteristics and the reading resolution of the magnetoresistive effect element 4 are improved.

Lower gap layer 11 and upper gap layer 1
2 is made of a non-magnetic insulating film such as Al ₂ O ₃ or SiO ₂ . In the MR head, these lower gap layers 1
1 and the lower shield layer 9 on which the upper gap layer 12 is disposed
The gap between the upper shield layer 10 and the magnetoresistive element 4 is defined as a read gap length G. In this case, the read gap length G is set to 100 nm.

When reproducing a signal from a magnetic recording medium using the MR head configured as described above, the magnetic recording medium is caused to travel so as to face the magnetoresistive effect element 4 and to read the signal from the magnetic recording medium. The signal magnetic field is detected by the magnetoresistive element 4. That is, the detection of the signal magnetic field by the magnetoresistive element 4 is performed by applying a sense current to the magnetoresistive element 4 via the front electrode 5 and the rear electrode 6 in a direction substantially perpendicular to the in-plane direction of the magnetic recording medium. This is performed by detecting the voltage change of the sense current. Note that this M
In the R head, the interval between the magnetoresistive elements 4 at the portion sandwiched between the insulating soft magnetic films 7 becomes the reproduction track width W.

Here, as a comparative example, an MR head in which the insulating soft magnetic film 7 is not disposed between the magnetoresistive effect element 4 and the hard magnetic film 8, ie, both ends of the magnetoresistive effect element 4 FIG. 6 shows a conventional MR head having the same configuration as the MR head to which the present invention shown in FIG. 5 is applied, except that the hard magnetic film 8 is provided. In FIG. 6, parts common to the MR head shown in FIG. 5 are denoted by the same reference numerals.

Then, as shown in FIG. 7, the magnetoresistive effect element when the track width W of the MR head to which the present invention shown in FIG. 5 is applied and the reproduction track width W of the conventional magnetic head shown in FIG. 6 are changed. 4 was measured. The reproduction track width W of these MR heads is 100 n
m, and the width W ^B of the insulating soft magnetic layer 7 shown in FIG. 5, 2
00 nm, and the sense current supplied to the magnetoresistive element 4 is constant. The output of the magnetoresistive element 4 of the MR head to which the present invention is applied shown in FIG. 5 is indicated by a thick line, and the magnetoresistive element 4 of the conventional MR head shown in FIG.
Is indicated by a thin line.

As is apparent from FIG. 7, the output of the magnetoresistive effect element 4 decreases as the reproduction track width W decreases in the conventional MR head, whereas in the MR head to which the present invention is applied, It can be seen that the output of the magnetoresistive element 4 does not decrease even when the reproduction track width W is reduced. That is, in the MR head to which the present invention is applied, similarly to the result shown in FIG.
It can be understood that the output of No. does not depend on the reproduction track width W.

As described above, in the MR head to which the present invention is applied, since the hard magnetic film 8 is provided on both sides of the magnetization free layer 1 with the insulating soft magnetic film 7 interposed therebetween, the hard magnetic film 8 Is applied to the magnetization free layer 1 via the insulating soft magnetic film 7. Thereby, this MR
In the head, even when the reproduction track width W is narrowed, the magnetic domains of the magnetization free layer 1 can be stabilized, and the output of the magnetoresistive element 4 can be prevented from lowering.

Therefore, in this MR head, the reproduction output does not depend on the reproduction track width W. For example, a high-density magnetic recording device such as a hard disk drive (HDD), a flexible disk drive (FDD), a magnetic tape drive, etc. , It is possible to obtain high reproduction output and improve off-track characteristics,
It is possible to cope with higher recording density.

In the MR head to which the present invention is applied, as shown in FIG. 8, the magnetoresistive element 4 may be, for example, a magnetoresistive element utilizing an anisotropic magnetoresistive effect. The magneto-resistance effect element 20 of a SAL (Soft Adjacent Layer) bias method may be used.

In this case, in the magnetoresistive element 20, the magnetization free layer 1 serves as the MR layer 21 such as NiFe, CoF
e, and a soft magnetic film having high magnetic permeability such as e.
b, made of a soft magnetic film of FeNiCr, permalloy, etc.
The nonmagnetic layer 3 is formed of, for example, a high resistance film such as Ta or an insulating film such as SiO ₂ or Al ₂ O ₃ as the intermediate layer 23.

As shown in FIG. 9, in the MR head to which the present invention is applied, the magnetization free layer 1 includes the nonmagnetic layer 3a,
3b, sandwiched between the magnetization fixed layers 2a, 2b.
A so-called double spin valve type magnetoresistive element 30 may be used.

In this case, in the magnetoresistive element 30, the magnetization free layer 1 is made of a soft magnetic film having a high magnetic permeability such as NiFe or CoFe, and the magnetization fixed layers 2a and 2b are
For example, the magnetization is fixed in a predetermined direction by an exchange coupling magnetic field acting between an antiferromagnetic film of IrMn, CoFe, Co, etc., for example, NiFe, CoFe, C
The nonmagnetic layers 3a and 3b are made of a soft magnetic film having a high magnetic permeability such as o, and the nonmagnetic layers 3a and 3b are made of a nonmagnetic film such as Au, Ag, and Cu.

As shown in FIG. 10, in the MR head to which the present invention is applied, a part of the soft magnetic film constituting the magnetization free layer 1 is replaced with the hard magnetic film 8 instead of the insulating soft magnetic film 7. The magnetoresistive element 40 may be extended to the side and provided with the hard magnetic film 8 via the extended soft magnetic film.

In this case, the magnetoresistance effect element 40 is
0, for example, a Ta layer 13 as a lower layer, a NiFe layer 14a and a CoFe layer 15 extending to the hard magnetic film 8 side as the magnetization free layer 1, and a C layer as the nonmagnetic layer 3
u layer 16, CoFe layer 17 and I
The nMn layer 18 and the Ta layer 19 as an upper layer are formed in this order.

In the MR head to which the present invention is applied, as shown in FIG. 11, the side portion of the magnetoresistive element 4 has a gentle taper shape, and the tapered side portion has an insulating property. The soft magnetic film 7a may be formed, and the hard magnetic film 8a may be formed so as to cover the insulating soft magnetic film 7a.

In FIGS. 8 to 11, parts common to the MR head shown in FIG. 5 are denoted by the same reference numerals. Further, the material of each layer constituting the MR head and the film thickness thereof are not limited to the above examples, but an appropriate material is selected according to the purpose of use of the MR head and the like, and an appropriate film thickness is obtained. What is necessary is just to set it.

In addition to the above-described configuration, the magnetization free layer 1 may be an artificial lattice multilayer film having a multilayer structure of a soft magnetic thin film and a non-magnetic thin film.
May be formed by electron beam drawing.

In the above description, only the MR head which is a read-only head has been described. However, if a recording / reproducing head is desired, an inductive magnetic head is formed on the MR head as a recording head. You may make it.

When an inductive magnetic head is laminated on the MR head, an inductive magnetic head may be newly formed on the MR head by a thin film process, or an inductive magnetic head may be formed on the MR head. The shield layer 10 may be used as a lower core layer of an inductive magnetic head, and a recording gap layer, a thin-film coil, an upper core layer, and the like constituting the inductive magnetic head may be formed on the lower core layer. .

[0077]

As described in detail above, in the magnetoresistive head according to the present invention, the hard magnetic film is provided on both sides of the magnetization free layer via the insulating soft magnetic film. A bias magnetic field from the hard magnetic film is applied to the magnetization free layer via the insulating soft magnetic film. This allows
In this MR head, even when the track width is reduced, the magnetic domains of the magnetization free layer can be stabilized, and the output of the magnetoresistive element can be prevented from being reduced. Therefore, with this MR head, the reproduction output does not depend on the track width, and it is possible to cope with a higher recording density.

[Brief description of the drawings]

FIG. 1 is a perspective view schematically showing a magneto-resistance effect element constituting a magneto-resistance effect type magnetic head to which the present invention is applied.

FIG. 2 is a graph showing a relationship between an output of a magnetoresistive element when a track width of the magnetoresistive head is changed.

FIG. 3 is a graph showing a distribution in a track width direction of a bias magnetic field from a hard magnetic film applied to a magnetization free layer of the same magneto-resistance effect type magnetic head via an insulating soft magnetic film.

FIG. 4 is a graph showing the distribution in the track width direction of the magnetic permeability of the magnetization free layer to which a bias magnetic field of the magnetoresistive head is applied.

FIG. 5 is an end view showing a configuration example of the magnetoresistive effect type magnetic head.

FIG. 6 is an end view showing a configuration of a conventional magnetoresistive magnetic head for comparison.

FIG. 7 is a graph showing the relationship between the track width of the magnetoresistive head shown in FIGS. 5 and 6 and the output of the magnetoresistive element when the track width is changed.

FIG. 8 is an end view showing another configuration example of the magnetoresistive head.

FIG. 9 is an end view showing another configuration example of the magneto-resistance effect type magnetic head.

FIG. 10 is an end view showing another configuration example of the magnetoresistive effect type magnetic head.

FIG. 11 is an end view showing another configuration example of the magnetoresistive head.

FIG. 12 is a perspective view schematically showing a magnetoresistive element constituting a conventional magnetoresistive magnetic head.

FIG. 13 is a graph showing the relationship between the track width of the magnetoresistive effect type magnetic head and the output of the magnetoresistive element when the track width is changed.

FIG. 14 is a graph showing a distribution in a track width direction of a bias magnetic field from a hard magnetic film applied to a magnetization free layer of the same magneto-resistance effect type magnetic head via an insulating soft magnetic film.

FIG. 15 is a graph showing the distribution in the track width direction of the magnetic permeability of the magnetization free layer of the magnetoresistive head to which a bias magnetic field is applied.

[Explanation of symbols]

1 magnetization free layer, 2 magnetization fixed layer, 3 non-magnetic layer, 4
Magnetoresistance effect element, 5 front electrode, 6 rear electrode, 7 insulating soft magnetic film, 8 hard magnetic film, 9 lower shield layer, 1
0 Upper shield layer, 11 Lower gap layer, 12 Upper gap layer

Claims (3)

[Claims] 1. A magnetoresistive head in which the direction of a sense current flowing through the magnetoresistive element is substantially perpendicular to the in-plane direction of the magnetic recording medium, wherein the magnetoresistive element has at least an external magnetic field. A magnetization free layer that changes the magnetization direction in response to the magnetization direction, and a magnetization fixed layer whose magnetization is fixed in a predetermined direction are laminated via a nonmagnetic layer. An insulating soft layer is provided on both sides of the magnetization free layer. A magneto-resistance effect type magnetic head, wherein a hard magnetic film is provided via a magnetic film. 2. The insulating soft magnetic film has a non-resistance of 20 μm.
2. The magneto-resistance effect type magnetic head according to claim 1, wherein said magnetic head is not less than Ωcm. 3. A magnetoresistive head according to claim 1, wherein said magnetoresistive element is a giant magnetoresistive element using a spin valve film.