JPH07254114A - Magnetic head - Google Patents

Abstract

(57) [Abstract] [Purpose] A magnetic head that can prevent Barkhausen noise, which causes variations in the characteristics of the magnetic head and noise, and that suppresses the reduction in head sensitivity even in narrow tracks, is particularly effective for the magnetoresistive effect type magnetic head. To provide. A magnetic domain control layer 60 and an electrode film 70 are disposed on the magnetoresistive film 50, and the magnetic domain control layer 60 has a conductive nonmagnetic film 55 and a magnetically soft ferromagnetic film 65 sequentially laminated. It is composed of a laminated film of two or more layers. As a result, it is possible to prevent the occurrence of a pole at the end portion of the magnetoresistive effect film, suppress the decrease in sensitivity without affecting the magnetoresistive effect film of the magnetic sensing portion, and suppress the magnetic domain control layer 60. It is possible to suppress the generation of a domain wall in the central portion of the magnetoresistive film by the longitudinal bias magnetic field generated from the above, and to suppress Barkhausen noise caused by the irregular movement of the domain wall.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head for narrow tracks, and more particularly to a magnetic head suitable for a magnetoresistive effect type having a magnetic domain control film for reducing Barkhausen noise.

[0002]

2. Description of the Related Art A magnetoresistive (MR) type thin film magnetic head generally applied to a magnetic disk device is a reproducing magnetic head utilizing a phenomenon in which the electric resistance of a magnetoresistive film is changed by magnetization from a magnetic disk. Yes, usually M combined with an inductive magnetic head for writing
It is used as an R / inductive composite magnetic head. As shown in FIG. 9A showing a composite magnetic head structure and FIG. 9B showing an enlargement of the MR head portion, this magnetoresistive effect magnetic head has a lower (magnetic) shield 10 made of a magnetic material and The magnetoresistive effect element 100 is arranged between the upper magnetic core 110 of the inductive magnetic head and the upper (magnetic) shield 90.

This magnetoresistive effect element 100 is a multilayer film including a magnetoresistive effect film and a bias film for applying a bias to the magnetoresistive effect film, and applies a longitudinal bias magnetic field to the magnetic domains of the magnetoresistive effect film. A magnetic domain control layer 60 and electrodes 70 for maintaining a single magnetic domain state are arranged at the upper and left ends.

This magnetoresistive effect magnetic head moves relative to the magnetoresistive film 100 by applying a lateral bias from the bias film and a detection current from the electrode 70 to the magnetoresistive film 100 so as to move relative to the magnetoresistive film 100. The data is reproduced by detecting the change in the resistance value of the detection current flowing through the magnetoresistive film that changes due to the magnetic field.

The problem with this magnetoresistive effect magnetic head is that
It is both high output and noise free. Many methods have been disclosed so far, and among them, a method in which only the both end regions of the magnetoresistive film are made into a single magnetic domain state by the magnetic domain control layer is effective. As an example of this magnetic domain control layer, an antiferromagnetic film acting as a magnetic domain control layer is directly formed on the upper side of the end of the magnetoresistive film as described in JP-A-62-40610, and the magnetic resistance is It is known that the upper end of the effect film is kept in a single magnetic domain state. In this technique, a magnetic domain control layer that applies a longitudinal bias magnetic field in the longitudinal direction of the magnetoresistive film is arranged only at the end of the magnetoresistive film, and this end is maintained in a single magnetic domain state. Further, Japanese Patent Application Laid-Open No. 2-220213 discloses a technique for realizing a single magnetic domain state by laminating a permanent magnet film on a non-magnetic film as a magnetic domain control layer of a magnetoresistive effect film. Similarly, as a document describing the magnetic domain control layer,
JP-A-3-120610 and JP-A-2-2202
No. 13 is cited, and these documents describe an example in which a nonmagnetic film and a permanent magnet film are continuously laminated as a magnetic domain control material.

[0006]

The magnetoresistive effect magnetic head according to the prior art described above has the following problems.

First, the antiferromagnetic film acting as the magnetic domain control layer described in the above publication is made of FeM as an antiferromagnetic material.
Although n-based and NiO are known, a FeMn-based antiferromagnetic film is poor in corrosion resistance, so a protective film must be provided.
Further, since NiO is an oxide and has excellent corrosion resistance, it cannot be formed on the magnetoresistive film because it is an insulating film, and the position of the end of the magnetic domain control layer and the position of the electrode interval cannot be determined by self-alignment. was there. By analogy with the strengths and weaknesses of the above two types of antiferromagnetic materials, the development of a conductive magnetic domain control film with excellent corrosion resistance can improve the sensitivity of the magnetoresistive effect magnetic head, but it has been realized so far. Absent.

Further, as a magnetic domain control material replacing the antiferromagnetic film described in the above embodiment, a magnetic domain control layer in which a nonmagnetic film and a permanent magnet film are continuously laminated is used, and the pattern end portion of the permanent magnet film is used. The resulting pollutions also affect the center of the magnetic sensitive portion of the magnetoresistive film, resulting in a problem that the magnetic field sensitivity is lowered. In the case of using this permanent magnet film, if the thicknesses of the non-magnetic film and the permanent magnet film on the magnetoresistive effect film can be optimized, it is considered that the influence on the magnetoresistive effect film of the magnetic sensing part can be reduced. In the film forming process, it is not possible to suppress variations in the thickness of the magnetoresistive film and the non-magnetic film and the permanent magnet film formed on the magnetoresistive film. It was unavoidable that the magnetic field sensitivity was deteriorated due to the influence of the poles generated from the end of the burner.

In particular, when the track width of the magnetic disk is narrowed due to the recent demand for high-density recording, most of the magnetically sensitive portion becomes a region with low magnetic field sensitivity, and output reduction is unavoidable. There was a problem that it was difficult to apply to the head.

An object of the present invention is to eliminate the above-mentioned problems caused by the conventional technique, and to provide a conductive magnetic domain control layer capable of suppressing Barkhausen noise without affecting the magnetoresistive film of the magnetic sensing section. The present invention is to provide a magnetoresistive effect type magnetic head having the same. In addition, a conductive magnetic domain control layer having excellent corrosion resistance and capable of suppressing a decrease in sensitivity and generation of Barkhausen noise without affecting the magnetoresistive film of the magnetic sensitive section, and a magnetic resistance having the conductive magnetic domain control layer An object is to provide an effect type magnetic head.

[0011]

To achieve the above object, the present invention provides a magnetoresistive effect film, an electrode for applying a detection current to the magnetoresistive effect film, and a lateral bias applied to the magnetoresistive effect film. In a magnetoresistive effect type magnetic head comprising a lateral bias film and magnetic domain control layers arranged at both upper ends of the magnetoresistive film, the magnetic domain control layer includes a non-magnetic film and a magnetically soft ferromagnetic film. The first feature is that it is a multi-layer film in which and are laminated.

Further, the present invention is a spin valve type which is composed of a first ferromagnetic film and a second ferromagnetic film separated by a thin metal layer, and has means for fixing the magnetization direction of at least one of the ferromagnetic films. The second feature of the magnetic head of the present invention is to provide a magnetic domain control layer of a multilayer film constituted by sequentially laminating a non-magnetic film and a magnetically soft ferromagnetic film as a means for fixing the magnetization direction. .

Further, according to the present invention, in the magnetic head according to the first or second feature, the non-magnetic film of the magnetic domain control layer is silver, copper, gold, an alloy thereof or a laminated film thereof. The third characteristic is that the thickness of the non-magnetic film of the magnetic domain control layer is thinner than the thickness of the magnetic film of the magnetoresistive effect film and the magnetic domain control layer.

[0014]

In the magnetic head according to the first feature, the magnetic domain control layers utilizing antiferromagnetic coupling are arranged above both ends of the magnetoresistive effect film, so that the pole at the end of the magnetoresistive effect film is formed. It is possible to prevent the occurrence of and the occurrence of, and to suppress the decrease in sensitivity without affecting the magnetoresistive effect film of the magnetic sensing section. Further, in this magnetic head, a domain wall is generated in the central portion of the magnetoresistive effect film due to a longitudinal bias magnetic field generated by antiferromagnetic coupling between the magnetoresistive effect film and the magnetic domain control layer provided on both ends of the magnetoresistive effect film. Can be suppressed, so that Barkhausen noise caused by the irregular movement of the domain wall can be suppressed.

The magnetic head according to the second feature uses a multi-layer magnetic domain control layer formed by sequentially laminating a non-magnetic film and a magnetically soft ferromagnetic film as a means for fixing the magnetization direction. It is also possible to suppress the decrease in sensitivity and the occurrence of Barkhausen noise, and contribute to the stabilization of the head characteristics. Further, in the magnetic head according to the first and second characteristics, the material and the thickness of the non-magnetic film are arbitrarily selected to further improve the corrosion resistance and the sensitivity without affecting the magnetoresistive film of the magnetic sensing part. And a Barkhausen noise can be suppressed.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a magnetoresistive magnetic head according to the present invention will be described in detail below with reference to the drawings. FIG. 1 shows an MR including a magnetoresistive effect magnetic head according to this embodiment.
FIG. 2 is a diagram for explaining the inductive composite magnetic head, and FIG. 2 is an enlarged perspective view of the magnetoresistive effect magnetic head according to the present embodiment. In FIG. 1, one half surface of the write head above the upper shield film 90 is omitted, and in FIG. 2, the upper gap film and the upper shield film 90 are omitted.

The MR / inductive composite magnetic head shown in FIG. 1 includes a lower magnetic shield 10 made of a magnetic material,
An upper magnetic shield 90 on which an upper magnetic core 110 of an inductive magnetic head is mounted, a magnetoresistive effect element 100 provided between the lower magnetic shield 10 and the upper magnetic shield 90, and the magnetic resistance. A magnetic domain control layer 60, which is a feature of the present embodiment and is arranged on both ends of the effect element 100.
And a pair of electrodes 70 for applying a detection current to the magnetoresistive effect element 100.

As shown in FIG. 2, the detailed structure of the magnetoresistive effect magnetic head is as follows: a lower gap film 20 formed on the lower magnetic shield layer 10; and a magnetic layer formed on the lower gap film 20. A soft bias film 30 for applying a soft bias magnetic field to the resistance effect film 50, a shunt film (metal thin film) 40 formed on the soft bias film 30 for applying a lateral bias to the magnetoresistive effect film 50, and this shunt film 40. The magnetoresistive effect film 50 formed thereon, a magnetic domain control layer 60 composed of a pair of layers formed at predetermined locations on the magnetoresistive effect film 50 at predetermined intervals, and the magnetic domain control layer 60 are the same. A signal extraction electrode 70 formed by a lift-off method, an upper gap film formed so as to cover each film / layer / electrode, and an upper magnetic film formed on the upper gap film. - and a field layer 90.

Next, the function and material of each layer / film will be described step by step. First, the upper / lower magnetic shield layers 90 and 10
Is arranged in order to prevent the magnetic field from the magnetic disk from affecting the magnetoresistive film 50 and to improve the signal resolution of the magnetoresistive head 100, and the material thereof is Ni.
Fe-based alloy / Co-based amorphous / Co-based crystalline and Fe-based crystalline, etc. are soft magnetic and the film thickness is approximately 0.5 to 3 μm.
Is desirable.

Upper and lower gap films 80 and 20
Is the soft film 30 / shunt film 40 / magnetoresistive effect film 5
Magnetoresistive element 100 and magnetic domain control layer 60
The magnetoresistive element 100 and the upper / lower magnetic shield layer 90/1 are arranged so as to sandwich the electrode 70 therebetween.
It acts to electrically and magnetically isolate 0 from each other, and is made of a non-magnetic and insulating material such as an alumina film. Further, the film thickness affects the reproduction resolution of the magnetoresistive effect magnetic head, and therefore depends on the recording density desired for the magnetic head,
Usually, it is in the range of 0.4 to 0.1 μm. Since the pressure resistance is weakened when the thickness of the gear-up films 80 and 20 is on the order of 0.1 μm, a bias is applied at the time of film formation or in a gas in which H ₂ and He are mixed with Ar as a sputtering gas. By forming a film or adding SiO ₂ or Ta ₂ O ₅ to alumina, the pinhole in the film is reduced, the film quality of alumina is improved, and the breakdown voltage is improved.

The soft bias film 30 generates a soft bias magnetic field by the magnetic field applied by the detection current flowing through the magnetoresistive film 50, and the soft soft magnetic field causes the non-magnetic layer (here, the shunt film 40) to intervene. Reverse bias is applied to the magnetoresistive film 50.

Generally, a shunt bias method and a soft film bias method are often used for bias application. The magnetization ratio between the soft film and the magnetoresistive film varies depending on how the bias method is used.
The range of 0.7 is desirable, and the soft film bias method alone is about 1.0. These values are the magnetoresistive film 50.
By selecting the material / thickness of, the amount of magnetization of the magnetoresistive effect film can be calculated and easily achieved by controlling the film thickness. By selecting the material of the soft film 30, the thickness can be limited so as to meet the predetermined magnetization ratio.

The shunt film 40 has a level sufficient to make the magnetoresistive film 50 highly sensitive, and a method using this shunt film is called a shunt bias method. The shunt film 40 is formed of a thin metal or alloy film of at least one kind such as Ti / Nb / Ta / Mo / W, which is usually 0.01, adjacent to the magnetoresistive film 50.
Generally, it is formed with a thickness of 0.05 μm. In this shunt bias method, the lateral bias magnetic field is changed by the current flowing through the shunt film 40, so that the shunt film 4
It is necessary to control the film thickness to 0, and the specific resistance value is usually 200 μΩ.
It is about −cm.

As described above, the magnetoresistive effect film 50 has a characteristic that the electric resistance changes depending on the magnetization from the magnetic disk, and as a material, a NiFe alloy film exhibiting excellent soft magnetic characteristics is well known. , The magnetostriction constant is 1 × 10 ^-6
It is desirable that the balance is 80 to 84 atomic% Ni in the range of -1 × 10 ^-6 and the balance is Fe. This is because the head characteristics are greatly affected by the stress-induced anisotropy, and it is desirable to reduce the absolute value. The material of the magnetoresistive film 50 may be a ferromagnetic thin film whose electric resistance changes depending on the direction of magnetization, such as a NiFeCo alloy film / NiCo alloy film.

The magnetic domain control layer 60, which is a feature of this embodiment.
Is a laminated film structure in which a non-magnetic film 55 and a magnetically soft ferromagnetic film 65 are sequentially laminated. The non-magnetic film 55 and the magnetically soft ferromagnetic film 65 are formed only on the left and right upper ends of the magnetoresistive effect film 50. The end portion is maintained in a single magnetic domain state by using antiferromagnetic coupling, and a longitudinal bias magnetic field in the longitudinal direction is applied to the magnetoresistive effect film 50. The non-magnetic film 55 and the magnetically soft ferromagnetic film 65 are coupled together by using antiferromagnetic exchange coupling. The action of this antiferromagnetic exchange coupling will be described later.

The magnetically soft ferromagnetic film 65 is most preferably made of the same material as the magnetoresistive film 50 in terms of control. This is because the film thickness is determined in terms of the magnetization ratio as described above. That is, when d is the film thickness / Bs is the saturation magnetic flux density and, for example, the thickness of the soft bias film 30 is expressed as “(d) software”, the relationship of the following expression 1 is desirable.

[0027]

## EQU1 ## (d) Soft = (Bs.multidot.d) Magnetoresistance / (Bs) Soft As the non-magnetic film 55, silver / copper / gold and an alloy or a laminated film of two or more kinds having good conductivity are predetermined. It is desirable to set the thickness. The reason for this is that the non-magnetic film controls the magnetic exchange coupling between the magnetic films 65 and 50 to stably obtain the antiferromagnetic coupling.

Next, FIG. 7 shows the relationship between the magnetic exchange interaction and the film thickness of the nonmagnetic film 55 interposed between the magnetoresistive film 50 and the magnetically soft ferromagnetic film 65. Figure 7
Is a magnetoresistive film 50 and a magnetically soft ferromagnetic film 6
It is shown that the magnetic exchange coupling state [antiferromagnetic coupling magnetic field Haf (Oe)] acting between the magnetic field and the magnetic field 5 varies depending on the thickness t of the non-magnetic film thickness 55. It is shown that as the non-magnetic film 55 has a vibrating characteristic, and the thicker the non-magnetic film 55, the smaller the coupling force itself, but the wider the margin of the non-magnetic film for antiferromagnetic coupling. This indicates that antiferromagnetic coupling can be maintained even if the thickness of the non-magnetic film varies, which means that the magnetic domain control method according to the present invention has a wide margin in film formation. There is.

Further, the characteristic stability of the non-magnetic film 55 in the thermal process is important, but it has been separately confirmed that the magnetic exchange coupling does not change in the thermal history up to 200 ° C., and during the head forming process. It is necessary to keep the maximum temperature of 200 ° C. or lower.

The signal extracting electrode conductor 70 has a sufficient current (for example, 1 × 10 ⁶ to 1 × 10 ⁶ to the magnetoresistive film 50).
Since a current of 1 × 10 ⁸ A / cm ² ) is applied, a thin film of copper, gold or the like having a sufficiently low electric resistance is usually desirable.

Next, the state of magnetic exchange coupling between the films and the layers of the magnetoresistive magnetic head having the above structure will be described with reference to FIG. FIG. 6 schematically shows the configuration of each film and layer shown in FIG. 2, and the spin moment direction of the magnetic ions when a current in each film and layer is applied is indicated by a thick arrow B / M. It is represented by / C. Arrow B in the figure
_LSR is the direction of the spin moment in the soft bias film 30, arrow M _LSR is the direction of the spin moment in the magnetoresistive film 50, and arrow C _LR is the magnetically soft ferromagnetic film 65.
Shows the direction of the spin moment of. This figure shows the magnetization direction when a current is applied.

In the magnetic exchange coupling state between these films and layers, when a detection current is applied to both ends of the magnetoresistive film 50 by electrodes 70 (not shown), the magnetoresistive film 50 is first detected.
A primary magnetic field (leftward direction) is generated by the current flowing through the magnetic field, and this magnetic field is applied to the soft bias film 30 and the magnetically soft ferromagnetic film 65 of the magnetic domain control layer 60. The soft bias film 30 to which this magnetic field is applied generates a rightward secondary magnetic field as indicated by arrow B, and the magnetically soft ferromagnetic film 65 of the magnetic domain control layer 60 is leftward tertiary as indicated by arrow C. Generates a magnetic field. These secondary and tertiary magnetic field, the magnetoresistive film 50 of the primary magnetic field, for example, both ends of the spin moment of the magnetoresistive film 50 affects as reference numeral 31 (arrow M _L
/ M _R ) is aligned in one direction, and this exchange bias is also transmitted to the central region (magnetically sensitive portion) of the magnetoresistive effect film 50, and a force for forcibly aligning the spin moment in the central region also acts in one direction. Magnetization of the same time soft bias film 30 the central region of the (arrow B _S) the inclination occurs saturation caused by the magnetic field (arrow M _S) resulting from the magnetoresistive film 50, the tilted spin moment (arrow B _S ) Is a magnetoresistive film 5
It acts on the magnetic field of 0 (arrow M _S ) and the longitudinal bias is applied.

As described above, in the magnetoresistive effect type magnetic head according to the present embodiment, the magnetically soft ferromagnetic film 65 of the magnetic domain control layer 60 causes the spin moments (arrows M _L / arrow) at both ends of the magnetoresistive effect film 50. (M _R ) is aligned in one direction, this exchange bias is also transmitted to the central region of the magnetoresistive effect film 50, and a force for forcibly aligning the spin moment in the central region also acts in one direction. Generation of domain walls in the central region can be suppressed, and Barkhausen noise can be prevented.

The magnetic domain control layer 60 is replaced with the magnetoresistive film 5.
The reason for providing only the end portion of 0 is to utilize that the center region is forced to be in the single magnetic domain state when the end portion is maintained in the single magnetic domain state. Further, in such a structure, the angle of the magnetic moment in the central region can be easily changed, so that it is possible to prevent the decrease in sensitivity that occurs when the magnetic domain control layer is formed on the entire magnetoresistive effect film 50. Further, in the central region of the magnetoresistive effect film, since the anisotropic magnetic field of the magnetoresistive effect film does not increase, the sensitivity of the magnetoresistive effect element does not decrease, and the decrease in head sensitivity can be prevented.

Next, an example of a method of manufacturing the magnetoresistive effect magnetic head will be described. The thin film forming method and the patterning method described below can use the well-known techniques such as the sputtering method, the etching method, and the lift-off method, but can also be manufactured by other methods.

First, a 2 μm thick permalloy film to be the lower magnetic shield layer 10 is formed on a non-magnetic substrate, and a 0.1 μm thick alumina film to form the lower gap film 20 is formed thereon. Then, on the lower gap film 20, 2
A soft film 30 with a thickness of 00 angstrom is provided, and further 1
A shunt film 40 having a thickness of 50 Å and a magnetoresistive film 50 having a thickness of 200 Å are sequentially laminated by a sputtering method, a vapor deposition method, or the like, and then unnecessary portions are removed by an ion milling method and patterned into a predetermined shape. Next, using the lift-off process method shown in FIG. 5, photoresist-PI two-layer coating, photoresist-P1
By patterning, deep UV cure undercut, sputtering metal film formation and photoresist-PI removal, a gold film to be the magnetic domain control layer 60 and the electrode 70 is formed to a thickness of about 0.1 μm. Subsequently, the lower magnetic shield 10 and the lower gap film 20 are patterned into a predetermined shape, and alumina forming the upper gap film 80 is formed to a thickness of 0.1 μm. Further, after forming a permalloy film as the upper magnetic shield layer 90 to a thickness of 2 μm, an alumina protective film is formed, and the manufacture of the magnetoresistive effect magnetic head is completed.

As described above, in the magnetoresistive effect type magnetic head according to the present invention, since the magnetic domain control layer and the electrode film are formed by the lift-off method, the magnetoresistive effect film 50 is not damaged during the manufacturing process. Since there is no risk of damaging the magnetoresistive effect film 50, the magnetoresistive effect film 5 having good magnetic characteristics.
0 can be formed, and a magnetoresistive magnetic head with stable performance can be manufactured.

Furthermore, the magnetic domain control layer according to the present invention can also be applied to a spin valve type magnetic head, and this embodiment will be described with reference to FIG.

The spin-valve type magnetic head according to the present embodiment is composed of first and second conductive ferromagnetic films above and below a conductive non-magnetic film, and has either the first or second strong magnetic film. The magnetic film is magnetically coupled to a magnetic domain control film that fixes the magnetization direction.

The magnetoresistive effect magnetic head according to this embodiment has a shunt film 40 / ferromagnetic film 65-as shown in FIG.
3 / nonmagnetic film 55 / ferromagnetic film 65-2 / magnetic domain control layer 60 composed of nonmagnetic film 55 and ferromagnetic film 65-1 / electrode 70
Is used to fix the magnetization direction of the magnetically soft ferromagnetic film 65-2 by magnetically exchange-coupling. This exchange coupling is performed between the multilayer films (two-layer film 6 in the figure).
It is determined by the antiferromagnetic coupling (between 5-1 and 65-2) and shows stable coupling to an external magnetic field. The magnetization direction of the magnetically soft ferromagnetic film 65 is the same as that of the ferromagnetic film 65-1 and the ferromagnetic film 6.
5-2 are antiparallel to each other and are perpendicular to the signal magnetic field. On the other hand, the ferromagnetic film 65-3 is controlled so as to have the same direction as the signal magnetic field. Further, it is possible to arrange the magnetic domain control layer on the substrate side by reversing the film configuration with respect to FIG. 8 in which the magnetic domain control layer is on the film surface side. As a result, it is possible to contribute to stabilization of the head characteristics of the spin valve magnetic head. In the figure, reference numeral 82 is an electric circuit for supplying a detection current, reference numeral 81 is a sensing means, and the magnetic domain control layer of the magnetoresistive effect magnetic head according to the present invention is It is formed simultaneously with the electrode film by using the lift-off method. Therefore, in the step of forming the magnetic domain control layer, there is no risk of damaging the magnetoresistive film, variation in performance among a large number of magnetic heads is suppressed, and it is advantageous for mass production. In the magnetic domain control structure of the present invention, which will be described later in Examples, when the film thickness of the magnetic domain control film changes by about 10%, the antiferromagnetic coupling force also changes, but it is at a level applicable to magnetic domain control.

Next, an example of a magnetic disk device to which the magnetoresistive magnetic head according to the above embodiment is applied will be described with reference to FIG. FIG. 3 is a schematic perspective view showing the internal structure of the magnetic disk device. In this device, a plurality of magnetic disks 203 held by a spindle 202, a motor for driving the spindle 202, and a movable carriage 20.
5, a magnetic head group 204 held by the magnetic head 5, a voice coil motor that drives the carriage 205, and a base 201 that supports these. Although not shown in the figure, a voice coil motor control circuit for controlling the voice coil motor according to a signal sent from a higher-level device such as a magnetic disk control device is provided. This device also
Read / write having a function of converting data sent from a host device into a current corresponding to a writing system and having a function of amplifying a data signal reproduced from the magnetic disk 203 and converting it into a digital signal. It has a circuit and an interface.

Next, the operation of this magnetic disk device will be described by taking the case of reading as an example. When an instruction of data to be read is given from the host device to the control circuit through the interface, this device causes the voice coil motor to drive the carriage by the control current from the voice coil motor control circuit, and the instructed data is transmitted. The magnetic head group 204 or the like is moved to the stored track position at high speed to perform accurate positioning. A data surface servo system is used for this positioning. That is, the servo information is recorded together with the data on the magnetic disk 203, and the positioning accuracy is improved by the servo information. Further, the motor supported by the base 201 rotates a disc 203 having a diameter of 3.5 inches or less attached to the spindle 202. Next, a predetermined magnetic head designated by the signal from the read / write circuit is selected, the head position of the designated area is detected, and then the data signal on the disk is read. This reading is performed by the magnetic head group 204 connected to the read / write circuit exchanging signals with the magnetic disk 203. The read data is converted into a predetermined signal.

In order to exert the effects of the magnetic head according to the present invention, it is desirable to mount the magnetic head on a magnetic disk device having a track density of 5000 tracks or more per inch as shown in FIG. For comparison, FIG. 4 shows the characteristics of the magnetic head according to the magnetic domain control method of the present invention and the characteristics of a conventionally known magnetic head using a permanent magnet film. The figure shows the change in sensitivity as the track width becomes narrower, and it can be seen that the sensitivity drops sharply in a magnetoresistive head having a track width of 2.5 μm or less in which a permanent magnet film is applied to magnetic domain control. This is because the poles generated at the end portions of the pattern of the permanent magnet film greatly affect the magnetic sensitive portion of the magnetoresistive film. On the other hand, in the magnetoresistive effect magnetic head according to the present embodiment, the sensitivity does not decrease even when the track width is narrow. This is because, as described above, the magnetic domain control layer of the present invention does not affect the magnetic sensitive portion of the magnetoresistive film and does not lower the magnetic field sensitivity. This means that the magnetic head using the present invention is compatible with narrow tracks.

[0044]

As described above, in the magnetic head according to the present invention, the magnetic domain control layer utilizing the antiferromagnetic coupling is arranged above both ends of the magnetoresistive effect film, so that the end of the magnetoresistive effect film is formed. It is possible to prevent the generation and generation of pollutants, and to suppress the decrease in sensitivity without affecting the magnetoresistive film of the magnetic sensing section. In addition, the present magnetic head uses a longitudinal bias magnetic field generated by the antiferromagnetic coupling between the magnetoresistive effect film and the magnetic domain control layer provided on both ends of the magnetoresistive effect film,
Since it is possible to suppress the generation of the domain wall in the central portion of the magnetoresistive film, it is possible to suppress Barkhausen noise caused by the irregular movement of the domain wall.

Further, in the magnetic head according to the present invention, as a means for fixing the magnetization direction, a multi-layer magnetic domain control layer constituted by sequentially laminating a non-magnetic film and a magnetically soft ferromagnetic film is used. It is also possible to suppress the decrease in sensitivity and the generation of Barkhausen noise and contribute to the stabilization of the head characteristics. Further, by arbitrarily selecting the material and thickness of the non-magnetic film, it is possible to further improve the corrosion resistance and suppress the decrease in sensitivity and the generation of Barkhausen noise without affecting the magnetoresistive film of the magnetically sensitive portion. it can.

[Brief description of drawings]

FIG. 1 is a diagram showing a magnetoresistive effect magnetic head according to an embodiment of the present invention.

FIG. 2 is an enlarged view of the magnetoresistive magnetic head shown in FIG.

FIG. 3 is a diagram showing a magnetic disk device to which a magnetic head according to the present invention is applied.

FIG. 4 is a diagram showing the relationship between head sensitivity and track width.

FIG. 5 is a process chart showing a typical lift-off process.

FIG. 6 is a schematic diagram for explaining the function of a magnetic domain control layer according to the present invention.

FIG. 7 is a diagram showing the relationship between the magnetic coupling and the non-magnetic film thickness of the magnetic domain control layer of the present invention.

FIG. 8 is a perspective view showing a spin valve type magnetic head for narrow tracks according to an embodiment of the present invention.

FIG. 9 is a diagram for explaining a magnetoresistive effect magnetic head according to a conventional technique.

[Explanation of symbols]

10 ... Lower magnetic shield layer, 20 ... Lower gap film, 3
0 ... Soft film, 40 ... Shunt film, 50 ... Magnetoresistive film, 55 ... Conductive non-magnetic film, 60 ... Magnetic domain control layer, 65 ...
Magnetically soft ferromagnetic film, 70 ... Signal detection electrode, 80
... upper gap film, 90 ... upper magnetic shield film, 100
... magnetic resistance effect type magnetic head, 110 ... upper magnetic core for write head, 201 ... base, 202 ... spindle,
203 ... Disc, 204 ... Magnetic head, 205 ... Carriage.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Kamio 2880 Kozu, Odawara City, Kanagawa Prefecture Storage Systems Division, Hitachi Ltd.

Claims (4)

[Claims] 1. A magnetoresistive effect film, an electrode for applying a detection current to the magnetoresistive effect film, a lateral bias film for applying a lateral bias to the magnetoresistive effect film, and upper end portions of the magnetoresistive effect film. In a magnetoresistive effect type magnetic head comprising a magnetic domain control layer arranged in
A magnetic head comprising a multi-layered film in which a non-magnetic film and a magnetically soft ferromagnetic film are laminated. 2. A spin-valve type magnetic head comprising a first ferromagnetic film and a second ferromagnetic film separated by a thin metal layer and having means for fixing the magnetization direction of at least one of the ferromagnetic films. 2. The magnetic head according to claim 1, further comprising a multi-layer magnetic domain control layer formed by sequentially laminating a non-magnetic film and a magnetically soft ferromagnetic film as a means for fixing the magnetization direction. 3. The magnetic head according to claim 1, wherein the non-magnetic film of the magnetic domain control layer is silver, copper, gold, an alloy thereof, or a laminated film thereof. 4. The magnetic head according to claim 1, wherein the non-magnetic film of the magnetic domain control layer is thinner than the magnetic films of the magnetoresistive film and the magnetic domain control layer.