JP2001084529A - Magnetic head and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a magnetic head magnetically stabler and simple in manufacturing procase, reduced in leakage magnetic field from a magnetic shield layer provided with a laminated structure of a ferromagnetic layer and an anti- ferromagnetic layer to a magnetoresistance effect layer. SOLUTION: This magnetic head is provided with a magnetic shielding layer 7 formed by laminating plural antiferromagnetic layers 71 and ferromagnetic layers and a magnetoresistance effect layer and executes recording of information to a magnetic recording medium and reproducing of information from the magnetic recording medium. At least one separating layer 73 for suppressing exchange interaction to the ferromagnetic layer 70 by the antiferromagnetic layers 71 is formed in the magnetic shielding layer 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head manufacturing method and a magnetic head for recording information on a magnetic disk and reproducing information from the magnetic disk, and more particularly to an inductive head and a magnetoresistive head. TECHNICAL FIELD The present invention relates to a method of manufacturing a composite magnetic head provided with a magnetic head and a magnetic head.

[0002]

2. Description of the Related Art With the recent increase in recording density of a magnetic disk device, a magnetic head using a spin valve element has been put to practical use as a read head of the magnetic disk.

FIG. 11 is a sectional view of a magnetic head using such a spin valve element. In this specification, a direction (first direction) that stands upright from a recording surface of a magnetic recording medium is defined as an X direction, a recording magnetization direction of a magnetic recording medium is defined as a Z direction, and a direction perpendicular to both the X and Z directions. Is a Y direction (a second direction).

As shown in FIG. 1, a magnetic head 1 comprises a substrate 2, a lower magnetic shield layer 3, a lower insulating layer 4, a spin valve element 5, an upper insulating layer 6, and an upper magnetic shield layer 7. , A gap insulating layer 8, a coil 10 insulated by an organic insulating layer 9, and an upper magnetic pole 11. The recording medium (not shown) in the magnetic head 1
The air bearing layer 12 is formed on the surface facing
An ABS layer made of S resin is formed.

In the magnetic head 1, the portion from the lower magnetic shield layer 3 to the upper magnetic shield layer 7 is a magnetoresistive read head. The magnetic pole of an inductive write head usually comprises a pair of magnetic poles.
Also serve as the lower magnetic pole of the write head. Therefore, the upper magnetic pole 1
1 is an inductive write head.

[0006] The magnetization of the magnetic pole is usually oriented in the Y direction within the air bearing layer 12. When a current is applied to the coil 10 of the inductive head, a magnetic flux is generated by electromagnetic induction, and the magnetization of the magnetic pole is oriented in the X direction. At this time, the magnetization of the magnetic recording medium is appropriately reversed by a magnetic field leaking from the ABS layer 12, and information is written in the Z direction which is the recording magnetization direction of the magnetic recording medium.

As a prior art of such a spin valve element of the magnetic head 1, the one shown in FIG. 12 is known.
This figure is a view as seen from the ABS layer 12 side in FIG. 11, and the same parts as those in FIG. 11 are denoted by the same reference numerals.

[0008] As shown in FIG.
Represents a first and a second ferromagnetic layers 51 and 52, a non-magnetic layer 53 separating the two ferromagnetic layers 51 and 52, and a second
And an antiferromagnetic layer 54 in contact with the ferromagnetic layer 52 of FIG. In addition, the magnetoresistive layer 5
At both ends of the magnetic layer 0, a magnetic domain control layer 55 for suppressing Barkhausen noise and an electrode layer 56 for flowing a sense current are provided.

The second ferromagnetic layer 52 includes an antiferromagnetic layer 5
4 is a fixed layer whose magnetization direction is substantially fixed. Magnetic materials such as Co and CoFe are used for the fixed layer, and PtMn, NiMn, CrMnPt, and MnI are used for the antiferromagnetic layer.
A magnetic material such as r is used. When these magnetic materials are used, the exchange coupling magnetic field for fixing the magnetization of the fixed layer is 200 Oe or more. The magnetization direction of the first ferromagnetic layer 51 rotates according to the signal magnetic field from the magnetic recording medium.
The first ferromagnetic layer 51 is called a free layer with respect to the fixed layer (in the following description, the first ferromagnetic layer is a free layer (51), and the second magnetic layer is a free layer ( 52)).

FIG. 13 is a schematic diagram showing a magnetization direction of the magnetoresistive layer 50 of the spin valve element 5 in a bias state. In this figure, parts common to those in FIG. 11 are denoted by the same reference numerals.

As disclosed in Japanese Patent Application Laid-Open No. 4-358310, in the spin valve element 5, the magnetization direction of the fixed layer 52 in the bias state is X, which is the direction of the signal magnetic field from the magnetic recording medium (magnetic disk) M. Direction, free layer 51
Is set in the Y direction which is a direction orthogonal to the magnetization direction of the fixed layer 52, a linear response to the signal magnetic field can be obtained.

In order to fix the magnetization direction of the fixed layer 52 to a predetermined direction, it is necessary to perform a heat treatment in a magnetic field at a temperature approximately equal to the blocking temperature of the antiferromagnetic layer 54.
Is inclined in the magnetization direction of the fixed layer 52. Therefore,
In order to realize the orthogonal relationship between the magnetization directions of the free layer 51 and the fixed layer 52 as described above, a heat treatment for magnetizing the magnetization direction of the fixed layer 52 and the easy axis of magnetization of the free layer are changed to the magnetization direction of the fixed layer 52. It is necessary to perform at least two or more heat treatments in a magnetic field of heat treatments different in the direction of the applied magnetic field for returning to the direction orthogonal to the above.

As a prior art for realizing the orthogonal relationship between the magnetization directions of the free layer and the pinned layer, Japanese Patent Application Laid-Open No. 10-222 discloses a conventional technique.
A technique disclosed in Japanese Patent Application Laid-Open No. 815 (hereinafter, referred to as Conventional Technique 1) is known.

In the prior art 1, after the fixed layer is first magnetized in the X direction, a heat treatment in a magnetic field for applying a magnetic field in the forward and reverse directions in the Y direction is performed for the same time in the forward and reverse directions.

By the way, in a so-called composite magnetic head including the above-described inductive type write head and magneto-resistance effect head, it is known that noise occurs in the magneto-resistance effect head immediately after the write operation by the inductive type head. . It is considered that the cause of the post-write noise is that a domain wall is generated in a portion of the upper magnetic shield layer in contact with the air bearing layer by the write operation, and the domain wall moves immediately after the end of the write.

As a conventional technique for suppressing post-write noise in such a composite magnetic head, US Pat.
The technique of No. 211 (hereinafter, referred to as conventional technique 2) is known. In this technology, the upper magnetic shield layer has a laminated structure of a ferromagnetic layer and an antiferromagnetic layer, and a magnetic domain of the upper magnetic shield layer is controlled by applying an exchange coupling magnetic field to the ferromagnetic layer of the upper magnetic shield layer. I have.

FIG. 14 shows an upper magnetic shield layer according to prior art 2 as an air bearing layer (A) in a magnetic head.
FIG. 3 is a view as viewed from the (BS layer) side. In this figure, parts common to those in FIG. 11 are denoted by the same reference numerals, and description thereof will be omitted. As shown in the figure, the upper magnetic shield layer 7 includes a ferromagnetic layer 71 and an antiferromagnetic layer 72.
, And the magnetizations of all the ferromagnetic layers 71 are magnetically stable against an external magnetic field due to the exchange coupling magnetic field from the antiferromagnetic layer 72 in contact therewith. Each ferromagnetic layer 71 is a Fe-based magnetic material having excellent soft magnetic properties, and the antiferromagnetic layer 72 is NiMn.

According to the prior art 2, the exchange coupling magnetic field for controlling the magnetic domain of the upper magnetic shield layer 7 is suitably from 3 to 10 Oe. The magnetization direction of the upper magnetic shield layer 7 in the prior art 2 is A
The magnetization direction of the upper magnetic shield layer 7 is oriented in the Y direction in the BS layer 12 and the fixed layer 52 of the spin valve element 5
At right angles to the magnetization direction (X direction). Therefore, when the spin valve element 5 and the magnetic domain-controlled upper magnetic shield layer 7 are used, the magnetization directions of the fixed layer 52 of the spin valve element 5 and the magnetic domain-controlled upper magnetic shield layer 3 are perpendicular to each other. A heat treatment for magnetizing is required.

As described above, a magnetic head in which a ferromagnetic layer and an antiferromagnetic layer are newly disposed in addition to the fixed layer of the spin valve element has been proposed. No method has been proposed for manufacturing a magnetic head in which the magnetization directions of the ferromagnetic layers fixed by the magnetic layers are orthogonal.

[0020]

As described above, in the spin valve element, it is necessary to make the magnetization direction of the fixed layer orthogonal to the direction of the easy axis of magnetization of the free layer in the bias state.

In prior art 1, in order to make the magnetization direction of the fixed layer orthogonal to the direction of the easy axis of magnetization of the free layer, the magnetization direction of the fixed layer is fixed, and then the direction of the easy axis of the free layer and the opposite direction. And heat treatment in a magnetic field is performed in each magnetic field atmosphere for the same time in the forward and reverse directions.

On the other hand, according to the prior art 2, since the upper magnetic shield layer in the composite magnetic head has a laminated structure of an antiferromagnetic layer and a ferromagnetic layer, noise after the write operation of the spin valve element can be suppressed. But for that,
It is necessary to make the magnetization direction of the fixed layer orthogonal to the magnetization direction of the upper magnetic shield layer.

However, if the heat treatment is performed by applying a magnetic field to the magnetization direction of the upper magnetic shield layer after fixing the magnetization direction of the fixed layer, the magnetization direction of the fixed layer is inclined to the direction of applying the magnetic field. Orthogonal relationship cannot be realized. At this time, as shown in the prior art 1, after the magnetization direction of the fixed layer is fixed, a magnetic field is applied in the magnetization direction of the upper magnetic shield layer and in the opposite direction to apply the magnetic field for the same time in the forward and reverse directions. If only the heat treatment is performed in a magnetic field, the magnetization of the upper magnetic shield layer is not fixed in a fixed direction, or only a very small exchange coupling magnetic field is obtained.

The magnetic shield layer according to the prior art 2 has the following problems. That is, the prior art 2
In order to control the magnetic domain of the upper magnetic shield layer as in the above, to obtain an exchange coupling magnetic field of 10 Oe using NiFe as the ferromagnetic layer and NiMn as the antiferromagnetic layer of the upper magnetic shield layer, the NiFe layer thickness becomes about It is as thin as 3500 angstroms. This is because the exchange coupling magnetic field between the ferromagnetic layer and the antiferromagnetic layer is inversely proportional to the saturation magnetization of the ferromagnetic layer. Therefore, it is necessary to reduce the thickness of the ferromagnetic layer in order to obtain a large exchange coupling magnetic field. Because there is. This 3500
When an upper magnetic shield layer having a total ferromagnetic layer thickness of 20,000 angstroms (2 μm) is to be formed using an Angstrom NiFe film, the NiFe / NiMn structure must be repeatedly laminated 5 to 6 times. It has to be complicated.

Further, when all the upper magnetic shield layers are formed in a laminated structure of a ferromagnetic layer and an antiferromagnetic layer as in the prior art 2, the following problem occurs. That is,
When the exchange coupling magnetic field between the ferromagnetic layer and the antiferromagnetic layer of the magnetic shield layer is sufficiently large, all the ferromagnetic layers of the magnetic shield layer are oriented in the Y direction parallel to the ABS layer to form a single magnetic domain. You. In this state, magnetization occurs at the end of the magnetic shield layer in the Y direction, and the magnetic field leaking outside the magnetic shield layer reaches the magnetoresistive layer. Since the leakage magnetic field changes depending on the magnetization state of the magnetic shield layer, the magnetic stability of the magnetoresistive layer is reduced.

Accordingly, an object of the present invention is to provide a composite magnetic head in which the upper magnetic shield layer has a laminated structure of an antiferromagnetic layer and a ferromagnetic layer, and has two antiferromagnetic layers, a magnetoresistive layer and an upper magnetic shield layer. When there is a ferromagnetic layer whose magnetization directions are fixed orthogonally to each other, it is possible to realize the orthogonal relationship and obtain a sufficient exchange coupling magnetic field,
As a result, it is an object of the present invention to provide a method of manufacturing a magnetic head capable of obtaining a stable reproduction output with suppressed noise.

It is another object of the present invention to reduce a leakage magnetic field from a magnetic shield layer having a laminated structure of a ferromagnetic layer and an antiferromagnetic layer to a magnetoresistive effect layer, to be more magnetically stable and to reduce the manufacturing process. It is to provide a simple magnetic head.

[0028]

According to the present invention, there is provided a magnetic shield layer comprising a plurality of antiferromagnetic layers and a plurality of ferromagnetic layers, a magnetoresistive layer having a fixed layer and a free layer. A method of manufacturing a magnetic head for recording information on a magnetic recording medium and reproducing information from the magnetic recording medium, comprising: a first step of forming the magnetoresistive layer; In a plane parallel to a plane including a first direction erecting from the recording surface of the magnetic recording medium and a second direction orthogonal to the first direction and the recording magnetization direction of the magnetic recording medium. A second step of directing in a third direction that intersects the first direction at an acute angle, a third step of forming the magnetic shield layer, and changing a magnetization direction of the ferromagnetic layer in the second direction. Magnetized to change the magnetization direction of the pinned layer to the first direction. It is characterized in that it comprises a fourth step of magnetizing the.

According to the present invention, in the method of manufacturing a magnetic head having the above-mentioned characteristics, the fourth step may include performing at least one heat treatment while applying a magnetic field in the second direction.
The first magnetic field heat treatment including at least one first magnetic field heat treatment and at least one second magnetic field heat treatment for performing a heat treatment while applying a magnetic field in a direction opposite to the second direction. The total time is made longer than the total time of the second magnetic field heat treatment.

According to another aspect of the present invention, there is provided a magnetic shield layer in which a plurality of antiferromagnetic layers and ferromagnetic layers are stacked, and a magnetoresistive layer, for recording information on a magnetic recording medium. In a magnetic head for reproducing information from a magnetic recording medium, at least one separation layer for suppressing exchange interaction between the antiferromagnetic layer and the ferromagnetic layer is formed on the magnetic shield layer. .

According to the present invention, in a magnetic head having the above characteristics, the sum of the product of the saturation magnetic flux density of the ferromagnetic layer subjected to exchange interaction by the antiferromagnetic layer and the thickness of the ferromagnetic layer is as follows: It is characterized in that it is equal to the sum of the products of the saturation magnetic flux densities of the other ferromagnetic layers not subjected to exchange interaction by the antiferromagnetic layer and the thicknesses of the other ferromagnetic layers.

In the magnetic head, the antiferromagnetic layer is made of an antiferromagnetic material, particularly, NiMn, MnPt, Mn.
It is preferable that the antiferromagnetic material be made of any one of PtPd, MnIr and CrMnPt.

In the magnetic head, it is preferable that one of the magnetic shield layers has one of the magnetic poles.

[0034]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Note that the present invention is not limited to the present embodiment.

FIG. 1 shows an embodiment of a magnetic head according to the present invention. In the figure, reference numeral 1 indicates a magnetic head. Parts common to those of the magnetic head 1 in the prior art shown in FIG. 11 are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 1, the magnetic head 1 according to the present embodiment includes a substrate 2, a lower magnetic shield layer 3, a lower insulating layer 4, a spin valve element 5, and an upper insulating layer 6.
, An upper magnetic shield layer 7, a gap insulating layer 8, a coil 10 insulated by an organic insulating layer 9, and an upper magnetic pole 11.

An air bearing layer 12 is formed on the surface of the magnetic head 1 facing the recording medium (not shown).

In the above configuration, the substrate 1, the lower magnetic shield layer 2, the lower insulating layer 3, the upper insulating layer 4, the gap insulating layer 8, the organic insulating layer 9, the coil 10, the upper magnetic pole 11,
As the air bearing layer 12, a normal air bearing layer conventionally used for this type of composite magnetic head 1 can be used.

As the free layer 51 and the fixed layer 52 made of a ferromagnetic layer in the spin valve element 5, the free layer 51 and the fixed layer 52 in the spin valve element 5 are conventionally used.
Ferromagnetic materials used as NiFe, CoFe, and NiFe can be used.
It is preferable to form a single layer made of any ferromagnetic material of Co or a laminated body of these.

As the non-magnetic layer 53 in the spin valve element 5, a non-magnetic material conventionally used as a non-magnetic layer can be used, but Cu is particularly preferable.

As the antiferromagnetic layer 51 in the spin valve element 5, an antiferromagnetic material conventionally used as an antiferromagnetic layer in a spin valve element can be used. NiMn, PtMn, PtPdMn, which has a high blocking temperature and a high exchange coupling energy while ensuring the stability of the reproducing operation in
It is preferable to use one of CrMnPt and MnIr antiferromagnetic materials.

In the magnetic head according to the present invention, the upper magnetic shield layer is formed by stacking a plurality of antiferromagnetic layers and a plurality of ferromagnetic layers. At least one separation layer for suppressing the action is formed.

In the upper magnetic shield layer having such a configuration, the magnetic field leaking from the ferromagnetic layer to which exchange coupling is added (subject to exchange interaction) from the antiferromagnetic layer is more likely to leak to the magnetoresistive layer. , It is easily absorbed by the ferromagnetic layer to which exchange coupling has not been added (no exchange interaction).

In the upper magnetic shield layer having such a structure, in particular, the sum of the product of the saturation magnetic flux density of the ferromagnetic layer subjected to exchange interaction from the antiferromagnetic layer and its thickness, and the antiferromagnetic layer It is particularly preferable that the sum of the products of the saturation magnetic flux density of the ferromagnetic layer which is not subjected to exchange interaction from the layer and the thickness thereof is equal. In such a configuration, there is no leakage of magnetic flux from the magnetic shield layer to the magnetoresistive layer, and the magnetization state of the magnetoresistive layer is affected by the magnetization state of the magnetic shield layer. Is improved.

Further, in such a configuration, the thickness of the ferromagnetic layer which is not subjected to the exchange interaction can be made large, so that the entire magnetic shield layer is formed by stacking the ferromagnetic layer and the antiferromagnetic layer. Compared with the magnetic shield layer of the technique 2, the number of layers is reduced, and the number of manufacturing steps can be reduced.

The number and location of the ferromagnetic layers in the upper magnetic shield layer are arbitrary, and can be appropriately changed as long as noise after writing can be suppressed. It is also possible to separate a stacked body of a ferromagnetic layer and an antiferromagnetic layer by a plurality of separation layers. Note that it is particularly preferable that the ferromagnetic layer and the antiferromagnetic layer are combined so as to obtain a large exchange coupling magnetic field.

As the ferromagnetic layer in the upper magnetic shield layer, a ferromagnetic material which has been conventionally used as a magnetic shield layer can be used, but it is excellent in soft magnetic properties, high in hardness and excellent in corrosion resistance. It is particularly preferable to use a ferromagnetic material of either NiFe or FeAlSi.

As the antiferromagnetic layer in the upper magnetic shield layer, an antiferromagnetic material conventionally used as a magnetic shield layer can be used, but a large exchange coupling with the above ferromagnetic layer is obtained. The following combinations are preferable, and in particular, NiMn, PtMn, PtPdM
It is preferable to use one of n, CrMnPt, and MnIr antiferromagnetic materials.

The separation layer in the upper magnetic shield layer is not particularly limited as long as it suppresses the exchange interaction between any one of the ferromagnetic layer and the antiferromagnetic layer in the upper magnetic shield layer. Can be used but
For example, it is preferable to use a material such as Ta which can easily control the crystal orientation of each magnetic layer.

In order to increase exchange coupling, an upper magnetic shield layer is provided between the ferromagnetic layer and the antiferromagnetic layer.
It is preferable to provide a layer made of Co or the like.

The antiferromagnetic layer of the upper magnetic shield is
It may be formed of the same material as the antiferromagnetic layer of the spin valve element, or may be formed of a different material.

As the upper magnetic shield layer, for example, the structure shown in FIG. 2 can be used.

The upper magnetic shield layer 7 shown in FIG. 2 includes two pairs of an antiferromagnetic layer 71 / a ferromagnetic layer 72 which are in contact with each other and a separation layer 7
3 and a ferromagnetic layer 70 in which the exchange interaction of the antiferromagnetic layer 71 is suppressed by the separation layer 73. The magnetic domains of the two ferromagnetic layers 72 are controlled by the exchange coupling magnetic field with the antiferromagnetic layer 71, and the magnetization is fixed in the Y direction in the air bearing layer (not shown). On the other hand, since the ferromagnetic layer 70 separated by the separation layer 73 is not in contact with the antiferromagnetic layer 71, its magnetization direction is not fixed.

The upper magnetic shield layer may be, for example, the upper magnetic shield layer 7 shown in FIGS. 3 to 5 in addition to the upper magnetic shield layer 7 of FIG. In these drawings, the same reference numerals are given to the same parts as those in FIG. 2, and the description thereof will be omitted.

Next, an embodiment of a method of manufacturing a magnetic head according to the present invention will be described with reference to FIG.

First, a lower magnetic shield layer and a lower insulating layer are formed on a substrate (Steps 1 and 2). The lower magnetic shield layer and the lower insulating layer can be formed by a usual method conventionally used in a method of manufacturing this type of magnetic head.

Next, a magnetoresistive effect layer is formed (Step
3). The formation of the magnetoresistive layer is performed by a usual method conventionally used in a method of manufacturing a magnetic head of this type. In the present invention, after this film formation, heat treatment in a magnetic field for magnetizing the fixed layer of the magnetoresistive effect layer is performed.

The magnetization direction of the fixed layer of the magnetoresistive effect layer is directed in the X direction that stands upright from the recording surface of the magnetic recording medium.
In consideration of the fact that the magnetization direction of the fixed layer is inclined by the heat treatment in the magnetic field at the time of the heat treatment of the organic insulating layer later, here X
Heat treatment in a magnetic field is performed while applying a predetermined magnetic field so as to be magnetized in a direction (third direction) inclined at a predetermined inclination angle に お い て in a plane parallel to a plane including the direction and the Y direction. This inclination angle Θ is preferably 0 ° <０ <25 °.

Next, a magnetic domain control layer and an electrode layer are patterned on both ends of the magnetoresistive layer, and an upper insulating layer, an upper magnetic shield layer, and a gap insulating layer are successively formed (Step 4 to Step 7).

Patterning of the magnetic domain control layer and the electrode layer,
In addition, the formation of the upper insulating layer and the gap insulating layer can be performed by an ordinary method conventionally used in a method of manufacturing this type of magnetic head.

Next, an organic insulating layer and a coil are formed (St.
ep8).

The method of forming the organic insulating layer and the coil can be performed by a usual method conventionally used in a method of manufacturing this type of magnetic head.

Then, during the heat treatment of the organic insulating layer, the magnetization direction of the ferromagnetic layer of the upper magnetic shield layer is magnetized in the Y direction,
A heat treatment in a magnetic field is performed to magnetize the magnetization direction of the fixed layer in the X direction.

This heat treatment in a magnetic field includes at least one first heat treatment step of performing a heat treatment while applying a magnetic field in the Y direction, and at least one first heat treatment step of performing a heat treatment while applying a magnetic field in a direction opposite to the Y direction. And a total heat treatment time of the first heat treatment step is preferably longer than a total heat treatment time of the second heat treatment step. For example, when the organic insulating layer is formed of a plurality of layers, it is preferable to perform the heat treatment by changing the applied magnetic field in accordance with the organic insulating treatment of each layer. The heat treatment of the insulating layer may be performed only once, and the magnetization direction of the fixed layer may be fixed in the X direction without applying a magnetic field during the heat treatment of the other organic insulating layer.

Further, by setting the inclination angle Θ of the initial magnetization direction of the fixed layer from the X direction to an appropriate angle, the maximum temperature in the first heat treatment step is made higher than the maximum temperature in the second heat treatment step. It is also possible to perform a heat treatment in a magnetic field in which the applied magnetic field during the first heat treatment step is higher than the applied magnetic field during the second heat treatment step.

After the above-described heat treatment in a magnetic field, an upper magnetic pole and a protective layer are formed (steps 9 and 10), and an air bearing layer is formed after polishing and the like.

According to the method of manufacturing a magnetic head of the present embodiment, the upper magnetic shield layer in the composite magnetic head has a laminated structure of an antiferromagnetic layer and a ferromagnetic layer, and the two layers of the magnetoresistive layer and the upper magnetic shield layer are formed. When there is a ferromagnetic layer whose magnetization directions are fixed orthogonal to each other by two antiferromagnetic layers, the orthogonal relationship can be realized and a sufficient exchange coupling magnetic field can be obtained, resulting in noise suppression. A stable reproduction output is obtained.

[0068]

The present invention will be described more specifically with reference to the following examples.

In this example, first, a lower shield layer, a lower insulating layer, and a magnetoresistive layer were formed on a glass substrate.

The fixed layer of the magnetoresistive effect layer is made of Co having a thickness of 20 angstroms, and the antiferromagnetic layer is made of Co having a thickness of 225.
Angstrom CrMnPt was formed.

The heat treatment in the magnetic field of the fixed layer is performed at 230 ° C. for 3 hours in a magnetic field of 3000 Oe so that the magnetization direction of the fixed layer after the heat treatment in the magnetic field is inclined at a desired angle か ら from the X direction. Was. The component in the X direction was 400 Oe.

Next, a magnetic domain control layer and electrode properties were patterned on both ends of the magnetoresistive layer, and an upper insulating layer, an upper magnetic shield layer, and a gap insulating layer were successively formed.

The structure and thickness of the upper magnetic shield layer are [T
a50 / NiFe800 / Co30 / CrMnPt40
0] 2 / Ta50 / NiFe 2000 (layer thickness unit: angstrom) (see FIG. 5 for the lamination structure).

In this embodiment, a laminated body of a NiFe layer 74 and a Co layer 75 is used as the ferromagnetic layer 72 of the upper magnetic shield layer. The magnetic domain of the ferromagnetic layer 72 is controlled by the exchange coupling magnetic field with the antiferromagnetic layer 71. The Co layer 75 is formed between the layers of NiFe and CrMnPt for the purpose of increasing the exchange coupling between the antiferromagnetic layer 71 and CrMnPt. The Ta layer (reference numeral 73 in FIG. 5) is formed as a separation layer 73 for separating the ferromagnetic layer 72 and the antiferromagnetic layer 71, and as a base layer for controlling the crystal orientation of the NiFe, Co, and CrMnPt layers. Formed. Uppermost ferromagnetic layer 7
Numeral 0 denotes a NiFe layer, which is separated by the separation layer 73 and is not in contact with the antiferromagnetic layer 71, so that the magnetic domain is not controlled by the antiferromagnetic layer 71.

In this embodiment, three organic insulating layers were formed, and each layer was subjected to a heat treatment at 230 ° C. for 3 hours. In this embodiment, a magnetic field is applied in the Y direction in which the magnetization of the lower magnetic shield layer is to be directed during the first and third heat treatments of the organic insulating layer, and the first and third organic insulation heat treatments are performed at the second heat treatment of the organic insulation layer. A magnetic field was applied in the -Y direction opposite to that during the layer heat treatment. The applied magnetic field is 600 Oe for any heat treatment of the organic insulating layer.
And

FIGS. 7 and 8 show the magnetization direction of the fixed layer and the X-direction component of the exchange coupling magnetic field in each step of the resistance effect layer in the magnetic head thus produced. In these figures, the direction of magnetization is Θ = 0 ° in the X direction, and a positive angle indicates that it is inclined in the Y direction in the XY plane. The 0th time is a value before the organic insulating layer processing is performed after the fixed layer of the magnetoresistive layer is magnetized. Since the actual magnetic field applied to the magnetoresistive layer during the heat treatment of the organic insulating layer is equivalent to 70 Oe, the applied magnetic field during the heat treatment of the organic insulating layer is 7.
0 Oe. As shown in FIG. 7, the magnetization direction of the fixed layer was Θ = −13 ° after the heat treatment of the magnetoresistive layer, but after the first heat treatment of the organic insulating layer, the magnetization direction was almost ０ = 0 °. confirmed. Then, after the second heat treatment of the organic insulating layer, the magnetization direction of the fixed layer was inclined by about 12 °,
It was confirmed that 有機 returned to 0 ° again after the third heat treatment of the organic insulating layer. Also, from the results in FIG. 8, the exchange coupling magnetic field of the fixed layer during these steps was as large as 400 Oe or more, and deterioration of the exchange coupling magnetic field due to the heat treatment was not observed.

FIGS. 9 and 10 show the magnetization direction and the coupling magnetic field in each step of the upper magnetic shield layer. The definition of the angle of the magnetization direction in FIG. 9 is the same as that in FIG. After the first heat treatment of the organic insulating layer, the magnetization direction of the upper magnetic shield layer was oriented in the original direction of 90 °, and the exchange coupling magnetic field was about 18 Oe. After the second heat treatment of the organic insulating layer, the magnetization of the upper magnetic shield layer was reversed, and the exchange coupling magnetic field was significantly reduced to about 5 Oe. This is because the heat treatment temperature of 230 ° C. is the blocking temperature of CrMnPt.
Because it is close to 75 ° C., about 70% of the magnetization was magnetized in the opposite direction. After the third heat treatment of the organic insulating layer, the magnetization of the upper magnetic shield layer was reversed again, and the exchange coupling magnetic field was recovered to about 12 Oe. It is the same reason that it does not completely recover until after the first heat treatment of the organic insulating layer,
This is because the heat treatment temperature of 230 ° C. is close to the blocking temperature of CrMnPt of 275 ° C. However, it was confirmed that a sufficient exchange coupling magnetic field was obtained to suppress noise after the write operation.

As described above, by performing the heat treatment in the magnetic field in the heat treatment of the organic insulating layer, the magnetization of the fixed layer is directed in the X direction, the magnetization of the upper magnetic shield layer is directed in the Y direction, and the magnetization of the fixed layer and the upper magnetic shield layer is changed. Can be made orthogonal to each other, and a sufficient coupling magnetic field of the fixed layer and the magnetic domain control layer of the upper magnetic shield layer can be obtained.

[0079]

According to the method of manufacturing a magnetic head and the magnetic head of the present invention, the following effects can be obtained.

According to the method of manufacturing a magnetic head according to the present invention, the magnetization of the upper magnetic shield layer whose magnetic domain is controlled by the antiferromagnetic layer and the magnetization of the pinned layer of the spin valve can be made orthogonal to each other, thereby achieving stable reproduction with reduced noise. A magnetic head capable of obtaining an output can be manufactured.

According to the magnetic head of the present invention,
Since the leakage magnetic field from the magnetic shield layer to the magnetoresistive layer is reduced, the magnetic stability of the magnetoresistive layer is improved.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a main part showing an embodiment of a magnetic head according to the present invention.

FIG. 2 is a schematic sectional view showing one mode of an upper magnetic shield layer in the magnetic head according to the present invention.

FIG. 3 is a schematic sectional view showing another embodiment of the upper magnetic shield layer.

FIG. 4 is a schematic sectional view showing another embodiment of the upper magnetic shield layer.

FIG. 5 is a schematic sectional view showing another form of the upper magnetic shield layer.

FIG. 6 is a flowchart showing a manufacturing procedure in a magnetic head manufacturing method according to an embodiment of the present invention.

FIG. 7 is a diagram showing a change in the magnetization direction of a fixed layer in an organic insulating layer heat treatment step in one embodiment of the method of manufacturing a magnetic head according to the present invention.

FIG. 8 is a diagram showing a change in an exchange coupling magnetic field of a fixed layer in an organic insulating layer heat treatment step in one embodiment of the magnetic head manufacturing method according to the present invention.

FIG. 9 is a diagram showing a change in the magnetization direction of a fixed layer in an organic insulating layer heat treatment step in one embodiment of the method of manufacturing a magnetic head according to the present invention.

FIG. 10 is a diagram showing a change in the exchange coupling magnetic field of the upper magnetic shield layer in the organic insulating layer heat treatment step in one embodiment of the magnetic head manufacturing method according to the present invention.

FIG. 11 is a schematic sectional view of a main part showing a configuration of a conventional composite magnetic head.

FIG. 12 is a schematic diagram showing a configuration of a spin valve element in a conventional composite magnetic head.

FIG. 13 is a schematic diagram showing a magnetization direction of a magnetoresistive layer of a spin valve element in a bias state.

FIG. 14 is a schematic diagram showing a configuration of an upper magnetic shield layer in a conventional composite magnetic head.

[Explanation of symbols]

1: magnetic head, 5: magnetoresistive layer, 7: upper magnetic shield layer (magnetic shield layer), 52: fixed layer, 71: antiferromagnetic layer, 72: ferromagnetic layer, 73: separation layer, M: magnetic Recording medium, X: first direction, Y: second direction, Z: recording magnetization direction.

Claims (4)

[Claims] A magnetic shield layer including a plurality of antiferromagnetic layers and a plurality of ferromagnetic layers, a magnetoresistive layer including a fixed layer and a free layer,
A method for manufacturing a magnetic head for recording information on a magnetic recording medium and reproducing information from the magnetic recording medium, comprising: a first step of forming the magnetoresistive layer; and a magnetization direction of the fixed layer. The first direction in a plane parallel to a plane including a first direction erecting from a recording surface of the magnetic recording medium and a second direction orthogonal to the first direction and a recording magnetization direction of the magnetic recording medium; A second step of directing the magnetic shield layer in a third direction intersecting at an acute angle to the direction; a third step of forming the magnetic shield layer; and a step of magnetizing the magnetization direction of the ferromagnetic layer in the second direction. ,
A fourth step of magnetizing the magnetization direction of the fixed layer in the first direction. 2. The method of manufacturing a magnetic head according to claim 1, wherein the fourth step performs at least one heat treatment in a first magnetic field while applying a magnetic field in the second direction. And performing at least one heat treatment in a second magnetic field while applying a magnetic field in a direction opposite to the second direction. A method for manufacturing a magnetic head, wherein the total time is longer than a total processing time of heat treatment. 3. A magnetic recording medium comprising: a magnetic shield layer having a plurality of antiferromagnetic layers and a plurality of ferromagnetic layers stacked; and a magnetoresistive layer, for recording information on a magnetic recording medium and reproducing information from the magnetic recording medium. The magnetic head according to claim 1, wherein at least one separation layer for suppressing exchange interaction between the antiferromagnetic layer and the ferromagnetic layer is formed on the magnetic shield layer. 4. The magnetic head according to claim 3, wherein
The sum of the product of the saturation magnetic flux density of the ferromagnetic layer subjected to the exchange interaction by the antiferromagnetic layer and the thickness of the ferromagnetic layer is equal to that of another ferromagnetic layer not subjected to the exchange interaction by the antiferromagnetic layer. A magnetic head characterized by being equal to the sum of the products of the saturation magnetic flux density and the thickness of the other ferromagnetic layer.