JPH04268207A - Magneto-resistance effect type reproducing head - Google Patents

Abstract

PURPOSE:To suppress the occurrence of Barkhausen noise and to micronize it. CONSTITUTION:The subject head is constituted by forming a ferromagnetic film 21 into an approximately V-shape extending on both sides of a signal magnetic field detecting area 21a in the middle in the slantwise upward directions to make wing areas 21b and 21c having comparatively wide areas. Antiferromagnetic films 22 and 23 for imparting a bias magnetic field to the signal magnetic field detecting area 21a to be turned into a single magnetic domain are layered on these wide wing areas 21b and 21c so as to constitute the head as well.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive read head.

In recent years, with the increase in the capacity of magnetic recording devices, which are external storage devices for computers, there has been a demand for high-performance magnetic heads. As a device that satisfies this requirement, it can be used even for small-diameter disks without depending on the speed of the recording medium.
Magnetoresistive reproducing heads, which can provide high output, are attracting attention.

[0003] Furthermore, there is a tendency for magnetic recording/reproducing devices to become smaller, and along with this, magnetoresistive effect type reproducing heads also tend to become smaller.

[0004] Therefore, a magnetoresistive reproducing head is required to have a minute size and a structure capable of suppressing Barkhausen noise.

[0005]

2. Description of the Related Art FIG. 8 shows a schematic diagram of a magnetoresistive effect type reproducing head 1 described in Japanese Patent Laid-Open No. 62-40610.

This head 1 has an MR sensor 4 made of a ferromagnetic film in an elongated pattern on the rear end surface (air outflow end surface) 3 of the slider 2. Lead-out conductors 5 and 6 from both ends of area 4a
is pulled out and the regions 4b on both end sides of the MR sensor 4
, 4c are coated with antiferromagnetic layers 7 and 8, and the entire structure is covered with a shield layer 9. antiferromagnetic layer 7,
8 functions to induce a single magnetic domain in the signal magnetic field detection region 4a of the MR sensor 4 in order to suppress Barkhausen noise caused by movement of domain walls within the MR sensor 4 due to the signal magnetic field.

[0007]

[Problems to be Solved by the Invention] As the head becomes smaller, the width dimension W1 in FIG.
, 4c becomes shorter, and both end regions 4b ,
The area of 4c becomes smaller.

[0008] When both end regions 4b and 4c become smaller,
It becomes difficult to laminate the antiferromagnetic films 7 and 8 here.

Furthermore, the antiferromagnetic films 7 and 8 are easily oxidized, and when oxidized, they lose their ability to induce a single magnetic domain. Therefore, the antiferromagnetic films 7 and 8 need to be placed slightly backward so as not to be exposed on the surface 10 facing the recording medium. If this is done in a situation where both end regions 4b and 4c are small, it becomes even more difficult to stack the antiferromagnetic films 7 and 8 on both end portions 4b and 4c.

Furthermore, since the areas of both end regions 4b and 4c are small, it is difficult to sufficiently apply the force for inducing a single magnetic domain by the antiferromagnetic films 7 and 8 to the signal magnetic field detection region 4a. .

That is, when the head 1 having the above structure is miniaturized, it becomes unable to sufficiently exhibit the Barkhausen noise generation suppressing effect.

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetoresistive reproducing head that can sufficiently suppress the occurrence of Barkhausen noise even when miniaturized.

[0013]

[Means for Solving the Problems] The invention as claimed in claim 1 provides a magnetoresistive read head in which a region of a ferromagnetic film for detecting a signal magnetic field is made into a single magnetic domain. a region for detecting a signal magnetic field; and a wing region located on both sides of the region and retreating from the surface facing the recording medium, and having a larger area than the signal magnetic field detection region. It has a V-shape, and has a structure in which antiferromagnetic films magnetized in the same direction as the longitudinal direction of the signal magnetic field detection region are laminated on the wing regions on both sides.

The invention according to claim 2 provides a magnetoresistive read head in which a region of a ferromagnetic film for detecting a signal magnetic field is made into a single magnetic domain, in which the ferromagnetic film is located at the center to detect a signal magnetic field. It has a substantially V-shape consisting of a sensing area and wing areas located on both sides of the sensing area and set back from the surface facing the recording medium and having a larger area than the signal magnetic field sensing area, The wing region on both sides has a structure in which ferrimagnetic films are laminated to apply a bias magnetic field to make the region into a single magnetic domain.

The invention according to claim 3 provides a magnetoresistive read head in which a region of a ferromagnetic film for detecting a signal magnetic field is made into a single magnetic domain, in which the ferromagnetic film is located at the center to detect a signal magnetic field. It has a substantially V-shape consisting of a sensing area and wing areas located on both sides of the sensing area and set back from the surface facing the recording medium and having a larger area than the signal magnetic field sensing area, Permanent magnets are stacked on the wing regions on both sides to apply a bias magnetic field to the signal magnetic field detection region to convert it into a single magnetic domain.

[0016]

[Operation] In the invention of claim 1, the ferromagnetic film is formed into a V-shape, which means that the wing region is set back from the surface facing the recording medium and has a large area, and the antiferromagnetic film is set back from the surface facing the recording medium. This makes it possible to stack the airfoils in a uniform arrangement and over the wing area.

The areas of the blade region and the antiferromagnetic film are large, and the force for converting the signal magnetic field detection region into a single magnetic domain is large.

The fact that the antiferromagnetic film is set back from the recording medium facing surface prevents the antiferromagnetic film from being exposed on the recording medium facing surface and prevents it from being oxidized.

In the invention of claim 2, the fact that the ferromagnetic film is V-shaped means that the wing region is set back from the surface facing the recording medium and has a large area, and the ferrimagnetic film is set back from the surface facing the recording medium. This makes it possible to stack them in a similar arrangement and over the wing area.

[0020] In the invention of claim 3, the ferromagnetic film is formed into a V-shape, so that the blade region is set back from the surface facing the recording medium and has a large area, and the permanent magnet is set back from the surface facing the recording medium. The arrangement allows for lamination over the wing area.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a magnetoresistive reproducing head 20 according to a first embodiment of the present invention. In the figure, parts corresponding to those shown in FIG. 8 are given the same reference numerals.

Reference numeral 21 denotes a ferromagnetic film made of NiFe, which is formed on the rear end surface 3 of the slider 2. This ferromagnetic film 21 has a substantially V-shape, and includes a signal magnetic field detection area 21a located at the center and exposed on the recording medium facing surface 10, and a signal magnetic field detection area 21a located at both ends of the signal magnetic field detection area 21a. Wing regions 21b, 21 extending diagonally upward and retreating from 10
c.

Each blade region 21b, 21c has a substantially inverted triangular shape with both ends of the signal magnetic field detection region 21a serving as vertices.

Even if the head 20 is miniaturized and its width W1 and length L1 become shorter, a certain level of height H1 can be ensured. For this reason, the wing region 21a
, 21b is a relatively large area S1 (=L1×H1/2), which is wider than the area S2 of the signal magnetic field detection region 21a.

Antiferromagnetic films 22 and 23 are FeMn films, respectively, and are formed to cover the wing regions 21b and 21c.

Here, since the area S1 of the blade regions 21b and 21c is relatively large, the antiferromagnetic films 22 and 23 can be formed without difficulty, and the area S3 thereof is large.

Further, the antiferromagnetic films 22 and 23 are formed to be set back by a dimension D from the recording medium facing surface 10. For this reason,
The antiferromagnetic films 22 and 23 are not exposed to the surface 10 and are completely covered by the shield layer 9, so that oxidation (corrosion) is reliably prevented.

The antiferromagnetic films 22 and 23 are formed in a magnetic field by applying a magnetic field in the direction of arrow A, which is the longitudinal direction of the signal magnetic field detection region 21a.

As a result, the antiferromagnetic films 22 and 23 are formed as shown in FIG.
, As shown in FIG. 2, in the direction of arrow A, one end is the south pole and the opposite end is the north pole.

Further, when looking within the thickness of the antiferromagnetic films 22 and 23, the direction of magnetization is as shown by the arrow in FIG.

Next, the function of the antiferromagnetic films 22 and 23 will be explained with reference to FIGS. 2 and 3.

First, as shown in FIG. 3, the antiferromagnetic film 22
and 23, the magnetization state of the wing regions 21b and 21c is made to be the same as the magnetization state 30 described above due to the interaction (indicated by the broken line arrow) with the magnetization state 30 in the direction of arrow A at the interface with the wing regions 21b and 21c. , the magnetization state is oriented in the direction of arrow A as shown by reference numeral 31.

Next, the interaction between the magnetization states 31 of the blade regions 21b and 21c is as shown by the broken line arrow in FIG.
It propagates sequentially within the ferromagnetic film 21 toward the signal magnetic field detection region 21a and reaches the signal magnetic field detection region 21a.

Here, although the signal magnetic field detection region 21a tends to have a structure having a plurality of magnetic domains separated by domain walls, the domain walls disappear due to the above-mentioned interaction.
It becomes a single magnetic domain without a domain wall.

Here, the area S3 of the antiferromagnetic films 22 and 23 is
covers the entire blade regions 21b and 21c, and the interaction between the antiferromagnetic films 22 and 23 covers the entire blade regions 21b and 21c.
Covers the whole thing. Therefore, although the area S1 of the blade regions 21b and 21c is large, the entire blade regions 21b and 21c are in a magnetized state 31 oriented in the direction of arrow A.

In this way, since the region in the magnetized state 31 is wide, this magnetized state 31 is in the signal magnetic field detection region 21a.
The strength of the interaction exerted toward the magnetic field is stronger than in the past, and the region 21a is more reliably made into a single magnetic domain than in the past.

Further, the antiferromagnetic films 22 and 23 are entirely covered with the shield layer 9, so that they do not oxidize and the blade regions 21b
, 21c connects without deterioration.

As a result, the head 1 having the above structure is small in size and has excellent characteristics that can reliably suppress the occurrence of Barkhausen noise.

FIG. 4 shows a magnetoresistive reproducing head 40 according to a second embodiment of the present invention.

In the figure, an antiferromagnetic film 41 which is a film of FeMn
, 42 are the same as those in FIG. 1, and corresponding parts are given the same reference numerals.

The antiferromagnetic films 41 and 42 have the same arrangement as the antiferromagnetic films 22 and 23, and are arranged in the wing regions 21b and 21c.
It is formed by covering the

The antiferromagnetic film 41 is formed in a magnetic field directed diagonally upward to the right, and as shown in FIG. 5, the direction of magnetization is the direction of the arrow 43.

Another antiferromagnetic film 42 is formed in a magnetic field directed diagonally downward to the right, and as shown in FIG. 5, the direction of magnetization is in the direction of an arrow 44.

Arrows 43 and 44 of each antiferromagnetic film 41 and 42
The action of the bias magnetic field directed in the direction of the blade regions 21b, 2
1c, and further extends to the signal magnetic field detection region 21a, and the region 21a is made into a single magnetic domain as shown in FIG.

As a result, the head 40 is small in size and has characteristics that can reliably suppress the occurrence of Barkhausen noise.

FIG. 6 shows a magnetoresistive reproducing head 50 according to a third embodiment of the present invention.

This head 50 has antiferromagnetic film 2 in FIG.
In this structure, ferrimagnetic films 51 and 52 are formed in place of ferrimagnetic films 2 and 23.

The effects of the ferrimagnetic films 51 and 52 propagate to the blade regions 21b and 21c, and further to the signal magnetic field detection region 21a, and the region 21a is made into a single magnetic domain.

As a result, the head 50 is small in size and has characteristics that can reliably suppress Barkhausen noise.

FIG. 7 shows a magnetoresistive reproducing head 60 according to a fourth embodiment of the present invention.

This head 60 has antiferromagnetic film 2 in FIG.
In this structure, permanent magnets 61 and 62 are formed in place of magnets 2 and 23.

The action of the permanent magnets 61 and 62
b, 21c, and further propagates to the signal magnetic field detection area 21
a and the region 21a is a single magnetic domain.

As a result, the head 60 is small in size and has characteristics that can reliably suppress the occurrence of Barkhausen noise.

[0054]

As explained above, according to the invention of claim 1, even if the size is minute, the signal magnetic field detection region can be effectively made into a single magnetic domain. Furthermore, it is possible to realize a highly reliable head in which the occurrence of Barkhausen noise can be suppressed and the antiferromagnetic film is prevented from being oxidized.

According to the invention of claim 2, even if the size is minute, the signal magnetic field detection region can be effectively made into a single magnetic domain, and even though the size is minute, Barkhausen noise is not generated. A head that can be suppressed can be realized.

According to the invention of claim 3, even if the size is minute, the signal magnetic field detection region can be effectively made into a single magnetic domain, and even though the size is minute, Barkhausen noise is not generated. A head that can be suppressed can be realized.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a first embodiment of a magnetoresistive read head of the present invention.

FIG. 2 is a diagram showing a ferromagnetic film and an antiferromagnetic film taken out from FIG. 1;

FIG. 3 is a sectional view taken along line III-III in FIG. 2;

FIG. 4 is a diagram showing a second embodiment of the magnetoresistive reproducing head of the present invention.

FIG. 5 is a diagram showing a ferromagnetic film and an antiferromagnetic film taken out from FIG. 4;

FIG. 6 is a diagram showing a third embodiment of the magnetoresistive reproducing head of the present invention.

FIG. 7 is a diagram showing a fourth embodiment of the magnetoresistive reproducing head of the present invention.

FIG. 8 is a diagram showing an example of a conventional magnetoresistive read head.

[Explanation of symbols]

2 Slider 3 Rear end surface 5, 6 Output conductor 9 Shield layer 10 Surface facing the recording medium 20, 40, 50, 60 Magnetoresistive reproducing head 21 Ferromagnetic film 21a Signal magnetic field detection region 21b, 21c Wing region 22, 23 Antiferromagnetic films 30, 31 Magnetization states 43, 44 Magnetization directions 51, 52 Ferrimagnetic films 61, 62 Permanent magnet

Claims (3)

[Claims] Claim 1: In a magnetoresistive read head in which a region of a ferromagnetic film for detecting a signal magnetic field is made into a single magnetic domain, the ferromagnetic film (21) is located at the center to detect the signal magnetic field. a region (21a), and wing regions (21b, 21a) located on both sides of the region, which are formed retreating from the surface (10) facing the recording medium and have a larger area than the signal magnetic field detection region (21a). 21c), and the wing regions on both sides (21b, 2
1c), an antiferromagnetic film (22, 23) magnetized to make the signal magnetic field detection region (21a) a single magnetic domain.
1. A magnetoresistive reproducing head characterized by having a structure formed by laminating layers. 2. In a magnetoresistive read head in which a region of a ferromagnetic film for detecting a signal magnetic field is made into a single magnetic domain, the ferromagnetic film (21) is positioned at the center to detect the signal magnetic field. a region (21a), and wing regions (21b, 21a) located on both sides of the region, which are formed retreating from the surface (10) facing the recording medium and have a larger area than the signal magnetic field detection region (21a). 21c), and the wing regions on both sides (21b, 2
1c), and a ferrimagnetic film (51, 52) that applies a bias magnetic field to convert the magnetic domain into a single domain. 3. In a magnetoresistive read head in which a region of a ferromagnetic film for detecting a signal magnetic field is made into a single magnetic domain, the ferromagnetic film (21) is positioned at the center to detect the signal magnetic field. a region (21a), and wing regions (21b, 21a) located on both sides of the region, which are formed retreating from the surface (10) facing the recording medium and have a larger area than the signal magnetic field detection region (21a). 21c), and the wing regions on both sides (21b, 2
1c), a magnetoresistive effect type reproducing head characterized in that permanent magnets (61, 62) are laminated to apply a bias magnetic field to the signal magnetic field detection region to make it a single magnetic domain.