JPH06215332A - Magneto-resistance effect type head - Google Patents

Abstract

PURPOSE:To effectively suppress the crosstalks from adjacent tracks at the time of signal reproduction. CONSTITUTION:This magneto-effect type head has an MR element 1, a pair of electrode layers 2, 2 for detecting the resistance change of the, MR element 1 and a pair of shielding layers 3, 4 disposed on both sides in the longitudinal direction of the tracks with the MR element 1 and the electrode layers 2, 2 in-between. A compensation conductor layer 5 of the width bestriding both electrode layers 2, 2 is disposed between these shielding layers 3 and 4. The induced electromotive voltage generated across the compensation conductor layer 5 is subtracted from the reproduced output voltage generated between the electrode layers 2 and 2, by which the reproduced output is compensated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive head (hereinafter referred to as MR head) including a magnetoresistive effect element (hereinafter referred to as MR element).

[0002]

2. Description of the Related Art In recent years, in order to cope with higher densities and miniaturization of various signal recording / reproducing devices such as hard disk devices and VTRs (video tape recorders), development of MR heads having excellent reproduction output characteristics is progressing. .

The MR head uses an MR element whose resistance value changes depending on the angle formed by the direction of current and the direction of magnetization, and detects a change in the signal magnetic field as a resistance change. The reproduction output voltage of the MR head is the medium-head. It has the feature that it does not depend on the relative speed between.

The basic structure of a conventional MR head is shown in FIG. The track width T is formed on the surface of the strip-shaped MR element (1).
_A pair of electrode layers (2) and (2) are formed at intervals corresponding to _W , and soft layers are formed on both sides of the MR element (1) and the electrode layers (2) and (2) in the track longitudinal direction. A pair of shield layers (3) and (4) made of a magnetic material are arranged.

The MR element (1) is patterned so as to have an easy axis of magnetization in its longitudinal direction (left and right direction in FIG. 5), and its end face is exposed at the contact surface with the recording medium (6) to give a signal. Detect magnetic field. MR element according to the signal magnetic field from the recording medium (6)
When the magnetization direction of (1) changes, the MR element
The resistance value of (1) changes, and the resistance value changes due to the pair of electrode layers.
(2) It is detected as a voltage change by (2).

In the MR head, the MR element (1)
Since the shield layers (3) and (4) are arranged above and below, a high reproduction resolution can be obtained.

[0007]

By the way, in the MR head, the aspect ratio of the MR element (1) is set as high as possible so that the magnetic domain structure can be easily made into a single magnetic domain, and so-called Barkhausen noise can be prevented. Planned. Therefore, the length of the MR element (1) in the track width direction is as large as several tens to hundreds of tens μm with respect to the track width T _W of several μm. Also, in order to facilitate the manufacturing process of the MR head, the length of the shield layers (3) and (4) in the track width direction is set to the MR element.
It is formed larger than the length of (1).

Therefore, the shield layers (3) and (4) are the MR elements.
Track T _L adjacent the tracks T _M to be reproduced by (1), straddles until the T _N, the adjacent tracks T _L, produces an effect to suck the magnetic flux generated from the T _N. The magnetic flux passes through the shield layers (3) and (4), and the MR element (1) and the electrode layer
(2) It flows into (2) and causes crosstalk from the adjacent tracks T _L and T _N.

Such crosstalk hinders an increase in track density, which hinders the miniaturization of a magnetic disk device and an increase in recording density. An object of the present invention is to effectively suppress crosstalk from adjacent tracks in a shield type MR head.

[0010]

In an MR head according to the present invention, a compensating conductor having a width across a pair of electrode layers (2) and (2) between a pair of shield layers (3) and (4). Layers (5) are placed,
The reproduction output is compensated by subtracting the induced electromotive voltage generated at both ends of the compensation conductor layer (5) from the reproduction output voltage generated between both electrode layers (2) and (2).

[0011]

The MR element (1) and the electrode layers (2) and (2) are considered to form a coil with one turn, and the shield layers (3) and (4)
An induced electromotive force is generated by the magnetic flux from the adjacent track attracted by the magnetic flux interlinking with the coil. This induced electromotive voltage causes noise due to the above-mentioned crosstalk.

In the MR head of the present invention, the number of turns of the compensation conductor layer (5) arranged between the shield layers (3) and (4) is one.
The coil of one time is composed, and the MR element (1) and the electrode layers (2) and (2)
The induced electromotive voltage of the same level as the electromotive voltage caused by Therefore, by subtracting the induced electromotive voltage generated at both ends of the compensation conductor layer (5) from the reproduction output voltage generated between both electrode layers (2) and (2), crosstalk noise is canceled and the resistance of the MR element (1) is reduced. Only the output voltage based on the change is obtained.

[0013]

According to the MR head of the present invention, it is possible to effectively suppress the crosstalk from the adjacent tracks, thereby increasing the track density, eventually reducing the size of the magnetic disk device, and increasing the recording density. Is achieved.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. As shown in FIG. 1, the MR head of the present invention is
A pair of shield layers (3) and (4) are arranged on both sides of the R element (1) and a pair of electrode layers (2) and (2) in the track longitudinal direction to form a shield type MR head. There is.

An MR element is provided between both shield layers (3) and (4).
On the upper part of (1) and the electrode layers (2) and (2), a compensation conductor layer (5) having a width extending over both electrode layers (2) and (2) is arranged. The compensation conductor layer (5) is made of a non-magnetic metal such as Au, Ag, Cu, Al. Also, between the shield layer (3) and the MR element (1), the MR
An insulating layer (not shown) is interposed between the element (1) and the compensating conductor layer (5) and between the compensating conductor layer (5) and the shield layer (4). A power source (7) for supplying a sense current to the MR element (1) is connected to the pair of electrode layers (2) and (2), and one end of the compensation conductor layer (5) is grounded.

In the MR head, a magnetic flux flow as shown by a broken line in FIG. 2 is formed during signal reproduction. The magnetic flux from the adjacent tracks attracted by the shield layers (3) and (4) interlinks not only with the MR element (1) and the electrode layers (2) and (2) but also with the compensating conductor layer (5). As a result, an induced electromotive voltage is generated at both ends of the electrode layers (2) (2) and the compensation conductor layer (5).

Therefore, in the MR head of the present invention,
As shown in Fig. 1, the output voltage from the electrode layer (2) and the compensation conductor layer
The output voltage from (5) is supplied to the mixer (8), and the electrode layer
The output voltage of the compensation conductor layer (5) is subtracted from the output voltage of (2), and the difference between the output voltages is amplified by the amplifier (9) and output to the subsequent circuit.

As a result, the crosstalk noise from the adjacent track is canceled, and faithful signal reproduction is realized based only on the output voltage corresponding to the resistance change of the MR element (1).

Next, a method of manufacturing the MR head of the present invention will be described. As shown in Fig. 3 (a), Al with a thickness of 2.6 mm
_An insulating layer 12 made of Al ₂ O ₃ having a thickness of 5 to 10 μm is formed on a substrate 11 made of ₂ O ₃ -TiC by a sputtering method. Further, a 1 μm-thick permalloy layer (13) serving as a lower shield layer is formed on the insulating layer (12) by an RF sputtering method, and the permalloy layer (13) is patterned into a rectangular shape of 150 μm × 200 μm by ion milling. Turn into.
For the formation of the permalloy film as the shield layer, -100V
Is applied to improve the film characteristics.

Thereafter, as shown in FIG. 3 (b), the permalloy layer (13)
After the SiO ₂ layer (14) is formed around the surface and the surface is flattened, a 0.1 μm thick SiO ₂ layer (15) is formed on the surface by a sputtering method to form an insulating layer.

Next, as shown in FIG. 3C, an MR element layer 16 is formed on the surface of the SiO ₂ layer 15. When the shunt bias method is adopted, a shunt layer is formed between the SiO ₂ layer (15) and the MR element layer (16). At this time, first, a Ti film to be a shunt layer was vapor-deposited to a thickness of 1000 angstrom, and subsequently, without breaking the vacuum in the same apparatus, permalloy (13 wt% Ni-19 wt% Fe) to be the MR element layer was formed. The film is deposited to a thickness of 400 Å. Here, at the time of vapor deposition of the permalloy film, a magnetic field of 70 Oe is applied to impart uniaxial anisotropy. The specific resistance of the permalloy film is about 23 μΩ · cm. Then, the permalloy film is subjected to ion milling and patterned into a rectangle of 5 μm × 100 μm so that the longitudinal direction is the easy axis of magnetization, and the MR element layer (16) is formed.

Thereafter, as shown in FIG. 4A, a pair of electrode layers (18) and (18) for supplying a sense current to the MR element layer (16) are formed. The electrode layer (18) is formed into a desired shape by using a well-known photolithography technique after forming a laminated film of Ti and Cu by a sputtering method. here,
The distance between the two electrode layers (18) and (18), which is the track width, was 5 μm. The film thickness of Ti and Cu is 200 angstroms and 2 respectively.
It was set to 000 angstroms.

As shown in FIG. 4A, SiO ₂ is formed around the electrode layer (18).
After forming the layer (17) and flattening the surface, an insulating layer (19) made of SiO ₂ having a thickness of 0.1 μm is formed on the surface by the sputtering method.

Further, as shown in FIG. 4 (b), a compensating conductor layer (21) made of a laminated film of Ti and Cu similar to the electrode layer is formed. At this time, the width of the compensation conductor layer (21) is made to coincide with the entire width of both electrode layers (18) and (18) by patterning using the photolithography technique. Then, a SiO ₂ layer (22) is formed around the compensation conductor layer (21) to flatten the surface.

As shown in FIG. 4 (c), an insulating layer (23) made of SiO ₂ having a thickness of 0.1 μm is formed by sputtering to cover the surfaces of the compensation conductor layer (21) and the SiO ₂ layer (22). Form. Further, a 1 μm thick permalloy layer (24) serving as a lower shield layer is formed on the insulating layer (23) by an RF sputtering method, and the permalloy layer (24) is patterned into a rectangular shape of 150 μm × 200 μm by ion milling. Turn into. afterwards,
An MR head is completed by forming a protective layer (25) of Al ₂ O ₃ having a thickness of 5 to 10 μm so as to cover the permalloy layer (24) by a sputtering method.

As shown in FIG. 1, the MR head has a power source (7),
By connecting to the mixer (8) and the amplifier (9) to supply the sense current to the MR element and canceling the output voltage of the compensation conductor layer (5) from the output voltage of the electrode layers (2) and (2) , It is possible to effectively suppress the crosstalk from the adjacent track when the signal is reproduced.

The above description of the embodiments is for explaining the present invention and should not be construed as limiting the invention described in the claims or reducing the scope. The configuration of each part of the present invention is not limited to the above-mentioned embodiment, and it goes without saying that various modifications can be made within the technical scope described in the claims.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing the basic configuration of an MR head according to the present invention.

FIG. 2 is a diagram showing a flow of magnetic flux in the MR head.

FIG. 3 is a process drawing showing the first half of the MR head manufacturing method according to the present invention.

FIG. 4 is a process drawing showing the latter half of the above manufacturing method.

FIG. 5 is a perspective view showing a conventional MR head.

[Explanation of symbols]

 (1) MR element (2) Electrode layer (3) Shield layer (4) Shield layer (5) Compensation conductor layer (6) Recording medium (7) Power supply (8) Mixer (9) Amplifier

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[Procedure amendment]

[Submission date] December 1, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction content]

Next, as shown in FIG. 3C, an MR element layer 16 is formed on the surface of the SiO ₂ layer 15. When the shunt bias method is adopted, a shunt layer is formed between the SiO ₂ layer (15) and the MR element layer (16). At this time, first, a Ti film to be a shunt layer was vapor-deposited to a thickness of 1000 angstrom, and subsequently, without breaking the vacuum in the same device, permalloy ( 81 wt% Ni-19 wt% Fe) to be the MR element layer The film is deposited to a thickness of 400 Å. Here, at the time of vapor deposition of the permalloy film, a magnetic field of 70 Oe is applied to impart uniaxial anisotropy. The specific resistance of the permalloy film is about 23 μΩ · cm. Then, the permalloy film is subjected to ion milling and patterned into a rectangle of 5 μm × 100 μm so that the longitudinal direction is the easy axis of magnetization, and the MR element layer (16) is formed.

Claims (1)

[Claims] 1. A magnetoresistive effect element (1) and a pair of electrode layers (2) for detecting a resistance change of the magnetoresistive effect element (1).
A magnetoresistive effect including (2) and a pair of shield layers (3) and (4) arranged on both sides of the magnetoresistive effect element (1) and the electrode layers (2) and (2) in the longitudinal direction of the track. In the mold head, a compensation conductor layer (5) having a width across both electrode layers (2) and (2) is arranged between both shield layers (3) and (4).
A magnetoresistive head capable of compensating the reproduction output by subtracting the induced electromotive voltage generated at both ends of the compensation conductor layer (5) from the reproduction output voltage generated between (2).