JPH07153036A - Magnetoresistance effect type magnetic head - Google Patents

Abstract

PURPOSE:To suppress Barkhausen noises and realize the improvement of a reproducing output by a method wherein a flux guide made of magnetic material is formed so as to have a long elliptical shape and the direction of the easy-to- magnetize axis of the flux guide is same as the direction of the easy-to- magnetize axis of an MR device, i.e., a direction parallel to a medium contact plane. CONSTITUTION:A flux guide 9 has a layer-built structure which is composed of a Ta film formed on the rear end part of an MR device 5 and first and second permalloy films formed on the Ta film successively. The flux guide 9 having the layer-built structure has a long elliptical shape whose long axis is approxymately perdendicular to the longitudinal direction of the MR device. That is, if the length of the flux guide 9 parallel to an ABS plane (a plane which is brought into contact with a magnetic recording medium) 7 is denoted by L and the width perpendicular to the ABS plane 7 is denoted by W, a relation L>W is satisfied and, further, both the edges 10 and 11 in the direction parallel to the plane 7 are formed to have circular-arc shapes. With this constitution, the magnetic domains of the guide 9 are not disturbed by a sensing current applied to the device 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive effect magnetic head suitable for reading information recorded on, for example, a hard disk.

[0002]

2. Description of the Related Art In recent years, a magnetoresistive effect type magnetic head (hereinafter referred to as MR head) using a thin film element such as permalloy having a magnetoresistive effect has been actively developed.

In such an MR head, the resistance of a thin film element made of permalloy changes due to a signal magnetic field leaking from the magnetic recording medium, and the information recorded on the magnetic recording medium can be read by detecting the resistance change. Is configured.

Since such an MR head is superior in sensitivity to short wavelengths as compared with a usual electromagnetic induction type magnetic head,
It is said that high sensitivity can be obtained in narrow track reproduction, short wavelength reproduction, and ultra-low speed reproduction.

The MR head has a magnetoresistive effect element (hereinafter referred to as an MR element) sandwiched by a pair of shield magnetic bodies, and a bias conductor for applying a bias magnetic field to the MR element is provided on the MR element. Generally, the structure is provided.

By the way, when the bias conductor is provided right above the MR element, the following inconvenience occurs. First
In addition, there is instability due to the magnetic effect of the lower shield magnetic material with the narrowing of the gap. That is, if there is a shield magnetic material immediately below the MR element, the domain wall of the MR element moves due to the disturbance of the magnetic domain of the core, which causes Barkhausen noise.

Secondly, the bias magnetic flux that has entered the bent MR element leaks to the lower shield magnetic body, causing non-uniformity of the bias magnetic field, resulting in reproduced waveform distortion and a reduction in linear recording density. .

Therefore, a bias magnetic field applying member for applying a bias magnetic field to the MR element provided between a pair of shield magnetic bodies is formed by forming a groove in the lower shield magnetic body in the lower layer and embedding it in the groove. Is proposed.

By thus embedding the bias magnetic field applying member in the groove formed in the lower shield magnetic body, the magnetic sensitive portion of the MR element sandwiched between the front electrode and the rear electrode and the lower shield magnetic body. The facing distance with
The bias magnetic field applied to the R element does not leak to the shield magnetic body. As a result, the bias distribution of the bias magnetic field applied to the MR element becomes uniform, the linearity is improved, and the linear recording density is improved.

However, when the groove portion is formed in the lower shield magnetic body, the magnetic resistance of the MR element is increased, and the MR element is substantially
The magnetic flux entering the element is reduced. Such a decrease in the signal magnetic field due to the magnetic resistance directly leads to a decrease in the reproduction output, which hinders the improvement of the linear recording density.

Therefore, in the prior art, as shown in FIG. 8, a flux guide 102 made of a magnetic material is formed on the rear end side of the MR element 101 on the side opposite to the contact surface with the magnetic recording medium. It is proposed that the flux guide 102 draws the signal magnetic flux entering the MR element 101 from the medium contact surface side toward the rear end side.

[0012]

However, the above-mentioned flux guide 102 has a horizontally long shape which is substantially rectangular in plan view, and its longitudinal direction is the same as the longitudinal direction of the MR element 101 (the direction in which the signal magnetic flux is drawn). Since it is provided, the easy axis of magnetization of the flux guide 102 is likely to be in the same direction as the signal magnetic flux drawing direction.

Therefore, the magnetic flux of the MR element 101 is moved in the flux guide 102 by the sense current flowing in the MR element 101 as shown in FIG. 8, and the magnetic domain of the MR element 101 provided thereunder is also induced to cause Barkhausen. Noise is generated.

Therefore, the present invention has been proposed in view of the above-mentioned technical problems of the related art, and secures magnetic stability, suppresses the generation of Barkhausen noise due to the movement of the domain wall, and reproduces. It is an object of the present invention to provide a magnetoresistive effect magnetic head capable of realizing an improvement in output.

[0015]

According to the present invention, a magnetoresistive effect element arranged so that its longitudinal direction is perpendicular to a contact surface with a magnetic recording medium, and a contact surface with the magnetic recording medium. A front end electrode laminated on the front end side of the magnetoresistive effect element, a rear end electrode laminated on the rear end side of the magnetoresistive effect element, and a magnetoresistive effect in which the front end electrode and the rear end electrode are laminated. A pair of shield magnetic bodies sandwiching the element, a bias magnetic field applying member for applying a bias magnetic field to the magnetoresistive effect element, and a flux guide made of a magnetic material laminated on the rear end side of the magnetoresistive effect element, The flux guide has a relationship of L> W, where L is the length in the direction parallel to the medium facing surface and W is the width in the perpendicular direction, and the easy axis of magnetization is the easy axis of the magnetoresistive element. Parallel to the medium facing surface Together form with the direction, by the end of a direction parallel to the media abutment surface arcuate,
The above problems are solved.

The flux guide is laminated on the magnetoresistive effect element via a Ta film, or is further stacked on the Ta film provided on the magnetoresistive effect element via a permalloy film having a thickness of 10 to 80 nm. It is formed by stacking permalloy films by plating. A magnetic material having a high magnetic permeability is used for this flux guide.

[0017]

In the present invention, the flux guide made of a magnetic material having a high magnetic permeability provided at the rear end portion of the MR element is provided in a direction orthogonal to the longitudinal direction of the MR element (direction parallel to the medium contact surface). ) Is formed as a vertically long shape so that the easy axis of magnetization is parallel to the medium contact surface like the easy axis of the MR element, so that the magnetic domain of the flux guide is stable. Therefore, generation of Barkhausen noise is avoided, and the signal magnetic flux entering the MR element is efficiently drawn from the ABS surface side to the rear side by this flux guide.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments to which the present invention is applied will be described in detail below with reference to the drawings. As shown in FIG. 1, the magnetoresistive effect magnetic head of this embodiment has a pair of shield magnetic bodies 1 and 2 formed on one side surface (not shown) of a slider, and these shield magnetic bodies 1. , 2
An MR element 5 having a front end electrode 3 and a rear end electrode 4 laminated in between, and a bias magnetic field applying member 6 for applying a bias magnetic field to the MR element 5 are configured.

Hereinafter, the shield magnetic body 1 formed in the lower layer will be referred to as the lower shield magnetic body 1, and the shield magnetic body 2 formed in the upper layer will be referred to as the upper shield magnetic body 2.

The MR element 5 is formed, for example, in a substantially rectangular pattern in a plan view, and is provided so that its longitudinal direction is perpendicular to a contact surface with the magnetic recording medium (hereinafter referred to as ABS surface 7). Has been. Also, this MR element 5
One side edge of the tip side of the is exposed to the ABS surface 7.

The MR element 5 is made of, for example, a ferromagnetic thin film such as permalloy, and is formed on the insulating film 8 functioning as a gap film provided on the lower shield magnetic body 1 by vacuum thin film forming means such as vapor deposition or sputtering. Has been formed.

The MR element 5 is an M made of permalloy.
The R thin film may be a single layer film, but a pair of MR thin films magnetostatically coupled may be laminated via a non-magnetic insulating layer made of, for example, SiO ₂ . With the laminated film structure, it is possible to avoid the occurrence of Barkhausen noise.

The tip electrode 3 is directly laminated on the tip of the MR element 5 so that one side edge thereof faces the ABS 7 and is electrically connected to the MR element 5.
The tip electrode 3 has a function as an electrode for supplying a sense current to the MR element 5 and also has a reproducing magnetic gap g.
It also functions as a gap film.

On the other hand, the rear end electrode 4 is laminated on the rear end side of the MR element 5 via the flux guide 9 for the purpose of improving the attraction of the signal magnetic field and making the bias distribution uniform.

As shown in FIG. 2, the flux guide 9 includes a Ta film 9a formed on the rear end portion of the MR element 5 and a first permalloy film 9b formed on the Ta film 9a by vapor deposition or sputtering. The second permalloy film 9c has a laminated film structure formed on the first permalloy film 9b by plating.

The Ta film 9a functions as a base film for the first permalloy film 9b formed on the Ta film 9a. Then, the first permalloy film 9b formed on the Ta film 9a.
Since the permalloy cannot be directly formed on the Ta film 9a by plating, it functions as a base film when the permalloy is electroplated. Further, the first permalloy film 9b has a property that magnetic anisotropy easily occurs when it is formed on the Ta film 9a.
The uppermost second permalloy film 9c is formed by the MR element 5
It plays the role of efficiently drawing in the signal magnetic flux that has entered into the rear end. When this second permalloy film 9c is plated on the first permalloy film 9b, the first permalloy film 9c is formed.
The plated film grows according to the magnetic anisotropy of b.

As shown in FIG. 3, the flux guide 9 having the laminated film structure as described above has a so-called vertically elongated elliptical shape so that its major axis is substantially perpendicular to the longitudinal direction of the MR element 5. Has been formed. That is, the flux guide 9 has a relationship of L> W, where L is the length in the direction parallel to the ABS surface 7 and W is the width in the vertical direction, and in the direction parallel to the ABS surface 7. Both edge portions 10, 11 are arcuate.

The arcuate end portions 10 and 11 of the flux guide 9 are further projected to the outside than the parallel surface portions 12 and 13 parallel to the ABS surface 7. And furthermore, this flux guide 9
Similar to the easy axis of magnetization of the MR element 5, the easy axis of magnetization is parallel to the ABS plane 7 shown by the arrow in FIG.

With this structure, magnetic domains having the orientation shown in FIG. 4 are generated in the flux guide 9, but since these magnetic domains flow back, the stability of the magnetic domains is maintained. Therefore, the magnetic domain of the flux guide 9 is not disturbed by the sense current flowing through the MR element 5, and as a result, the magnetic domain of the MR element 5 is also stabilized.

Further, when the flux guide 9 is provided on the rear end side of the MR element 5, instability such as Barkhausen noise due to the flux guide 9 may be a concern. No such instability is observed in the conversion characteristics, and a good output waveform as shown in FIG. 7 is obtained.

The bias magnetic field applying member 6 is for applying a bias magnetic field to the MR element 5, and the tip electrode 3
Between the rear end electrode 4 and the rear end electrode 4, the groove 14 is formed in the lower shield magnetic body 1 on the side opposite to the side where the electrodes 3 and 4 are provided, and is embedded in the insulating film 15. ing.

The bias magnetic field applying member 6 has the above-mentioned A
It serves to apply a bias magnetic field over the longitudinal direction of the MR element 5 which is a direction perpendicular to the BS plane 7. The bias magnetic field applying member 6 may be, for example, a conductive conductor or a hard film (a permanent magnet having a high coercive force and a high saturation magnetic flux density). When the bias magnetic field applying member 6 is a conductor, a bias current from a DC power source is applied to both terminals of the conductor pattern in the track width direction which is the longitudinal direction of the wiring pattern.

The pair of shield magnetic bodies 1 and 2 provided so as to sandwich the MR element 5 from above and below,
It functions as a shield that is not affected by the magnetic field from the medium located away from the MR element 5, and is formed of, for example, permalloy or the like. Of these shield magnetic bodies 1 and 2, the lower shield magnetic body 1 is
This AB is made to face one side edge on the BS surface 7.
It is provided so as to extend in a direction perpendicular to the S surface 7.

Then, in the lower shield magnetic body 1,
A groove portion 14 for embedding the above bias magnetic field applying member 6 with an insulating film 15 is provided at a position corresponding to a region sandwiched by the front electrode 3 and the rear electrode 4. Such groove 14
Is a groove having a substantially U-shaped cross section having a bottom surface 14a parallel to the bias magnetic field applying member 6 and inclined surfaces 14b and 14c formed on both sides of the bottom surface 14a so as to widen the opening width of the groove. It is formed in the short side direction (track width direction) of the lower shield magnetic body 1.

Of the inclined surfaces 14b and 14c, the ABS
The groove tip portion D ₁ of the inclined surface 14b provided on the surface 7 side that is close to the MR element 5 is located at substantially the same position as the rear end portion (position of the depth zero of the reproducing magnetic gap g) E _{1 of the} tip electrode 3. ing. On the other hand, the MR element 5 of the other inclined surface 14c
Groove rear end D ₂ adjacent to is the rear with respect to the distal end portion E ₂ of the flux guide 9. When viewed in the opposite way, the tip E ₂ of the flux guide 9 is
It is provided closer to the ABS surface 7 with respect to the groove rear end portion D ₂ . That is, if the flux guide 9 is provided closer to the ABS surface 7 than the groove rear end portion D ₂ of the groove portion 14,
The MR element 5 is more easily biased.

On the other hand, like the lower shield magnetic body 1, the upper shield magnetic body 2 provided so as to face the upper shield magnetic body 2 has its one side edge facing the ABS surface 7.
It is provided so as to extend perpendicularly to the BS surface 7 toward the back side. Further, the upper shield magnetic body 2 has an ABS surface 7
Is laminated directly to the tip electrode 3 on the side, and is laminated on the rear side with the insulating layer 16 interposed.

To form the flux guide 9, the Ta film 9a is first formed on the MR element 5 by vacuum thin film forming means such as sputtering or vapor deposition. The thickness of the Ta film 9a is preferably 100 nm or less, for example. Further, this Ta film 9a has a small diffusion to the MR element 5 when heat is applied in the process.

Next, sputtering is performed on the Ta film 9a.
Alternatively, the first permalloy film 9b is formed by vapor deposition.
The thickness of the first permalloy film 9b is, for example, 1
It is set to 0 to 80 nm. If the film thickness is less than 10 nm
It becomes difficult to have anisotropy when it exists, and it becomes the second when it exceeds 80 nm.
No magnetic coupling can be made to the permalloy film 9c.
In this embodiment, the thickness of the first permalloy film 9b is set to 80 n.
m. The first permalloy film 9b and the second permalloy film 9b
The magnetostriction constant of the Malloy film 9c is −0.5 × 10.^-6~ -1.
0x10 ^-6Is desirable.

As a result, as shown in FIG. 5, magnetic anisotropy is given to the first permalloy film 9b.

Then, a second permalloy film 9c is formed on the first permalloy film 9b by electroplating. The film thickness at this time is preferably thicker in consideration of the stability of the magnetic domain, but if it is too thick, it becomes a step and this is reflected in the subsequent steps, and in particular, the magnetic characteristics of the upper shield magnetic body 2 may be disturbed. It is desirable to set the thickness to about 300 nm.

In this embodiment, the thickness of the second permalloy film 9c is 220 nm.

At this time, a plating film grows on the second permalloy film 9c according to the magnetic anisotropy imparted to the first permalloy film 9b. The result is shown in FIG. As can be seen from this figure, the second permalloy film 9c is given anisotropy by reflecting on the magnetic anisotropy of the first permalloy film 9b.

Finally, after patterning the flux guide 9 into the shape described above, the flux guide 9 is etched to complete the flux guide 9.

In the above example, the flux guide 9
Although permalloy is used as the above, the same effect can be obtained by using a magnetic material having a high magnetic permeability such as sendust or an Fe—Co based amorphous material.

[0045]

As is apparent from the above description, in the magnetoresistive effect magnetic head of the present invention, the flux guide made of a magnetic material having a high magnetic permeability is provided at the rear end of the MR element. The magnetic domain of the flux guide is formed as an elliptical shape that is vertically long in the direction orthogonal to the longitudinal direction of the element, and its easy axis of magnetization is parallel to the medium contact surface like the easy axis of magnetization of the MR element. As a result, the Barkhausen noise can be prevented from occurring, and the reproduction output can be significantly improved.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of an MR head.

FIG. 2 is an enlarged sectional view of a flux guide.

FIG. 3 is an enlarged plan view of a flux guide.

FIG. 4 is a schematic diagram showing magnetic domains generated in a flux guide.

FIG. 5 is a characteristic diagram showing that anisotropy occurs when a first permalloy film is formed on a Ta film.

FIG. 6 is a characteristic diagram showing that the anisotropy of the first permalloy film is reflected when the second permalloy film is formed on the first permalloy film by plating.

FIG. 7 is a characteristic diagram showing a reproduced waveform in the MR head of the present embodiment.

FIG. 8 is an enlarged plan view of a conventional horizontally long flux guide.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Lower shield magnetic body 2 ... Upper shield magnetic body 3 ... Front electrode 4 ... Rear end electrode 5 ... MR element 6 ... Bias magnetic field application member 7 ... ABS surface 9 ... Flux guide 9a ... Ta film 9b ... First permalloy film 9c ... Second permalloy film

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Mamoru Sasaki 6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation (72) Hideichi Haga 6-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation (72) Inventor Hideo Suyama 6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation

Claims (4)

[Claims] 1. A magnetoresistive effect element arranged such that its longitudinal direction is perpendicular to a contact surface with a magnetic recording medium, and a magnetoresistive effect element facing the contact surface with the magnetic recording medium. A front end electrode laminated on the front end side, a rear end electrode laminated on the rear end side of the magnetoresistive effect element, and a pair of shield magnetic bodies sandwiching the magnetoresistive effect element in which the front end electrode and the rear end electrode are laminated. A bias magnetic field applying member for applying a bias magnetic field to the magnetoresistive effect element, and a flux guide made of a magnetic material laminated on the rear end side of the magnetoresistive effect element. When the length in the direction parallel to the plane is L and the width in the direction perpendicular to the plane is W, the relation L> W is established, and the easy axis of magnetization is the same as the easy axis of the magnetoresistive element with the medium facing surface. With the parallel directions ,
A magnetoresistive effect magnetic head, characterized in that an end portion in a direction parallel to the medium contact surface is arcuate. 2. The magnetoresistive effect magnetic head according to claim 1, wherein the flux guide is laminated on the magnetoresistive effect element with a Ta film interposed therebetween. 3. The magnetoresistive effect magnetic head according to claim 1, wherein the flux guide is made of a magnetic material having a high magnetic permeability. 4. The flux guide comprises a Ta film provided on a magnetoresistive element, a first permalloy film having a thickness of 10 to 80 nm formed on the Ta film by vapor deposition or sputtering, and a first permalloy film. 1. A magnetoresistive effect magnetic head having a laminated film structure of a second permalloy film laminated on one permalloy film by plating.