JPH11126313A - Magneto-resistive element, magneto-resistive head and magnetic disk device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic disk device of a high recording density by eliminating the generation of side lobes which are the off-track characteristic intrinsic to an MR head. SOLUTION: Antiferromagnetic films 10, 11 for single magnetic domaining of MR films 9 are joined to both right and left sides of the MR films 9. The intensity of the exchange coupled magnetic field (Hex) between the MR films 9 and the antiferromagnetic films 10, 11 is specified to >=135 oersteds. As a result, the side lobes of the off-track characteristics are decreased and the crosstalks from adjacent tracks are decreased and, therefore, high-density recording and reproducing may be embodied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a magnetoresistive element, a magnetoresistive head, and a magnetic disk drive using the same.

[0002]

2. Description of the Related Art Conventionally, a magnetoresistive head (hereinafter referred to as an MR head) using a magnetoresistive element of this type (hereinafter referred to as an MR element) emits light from a magnetic recording medium using the magnetoresistive element. It is a magnetic head dedicated to reproduction (reading) for detecting recorded magnetic fields and reproducing recorded information. Usually, this MR head and recording (writing)
By combining the magnetic head with an inductive magnetic head, the magnetic head is mounted on a magnetic disk device as an inductive / MR composite magnetic head (hereinafter, referred to as a composite magnetic head).

FIG. 2 is a front view showing an example of a conventional composite magnetic head as viewed from a surface facing a recording medium. Referring to FIG. 2, the composite magnetic head 1 is configured by laminating an inductive magnetic head 3 on an MR head 2.

In the MR head 2, a lower shield 5 is formed on a slider substrate 4, and a lower gap 6 forming an insulating layer is laminated thereon. On the lower gap 6, a SAL bias film (Soft Adjacent Layer: proximity soft magnetic layer) 7, a spacer film 8, and an MR film 9 are sequentially laminated. An antiferromagnetic film 10 and an antiferromagnetic film 11 for making the single magnetic domain are joined.

Further, an electrode film 12, an electrode film 1
The upper gap 14 and the upper shield 15 that constitute an insulating layer are laminated on the MR film 9 and the electrode films 12 and 13.

On the other hand, in the induction type magnetic head 3, the upper shield 15 of the MR head 2 is also used as a lower core, and a write gap 16, a coil and an insulating layer (not shown), an upper core 17, and a protective film are formed thereon. 18 are sequentially laminated.

In the composite magnetic head 1 thus constructed, a recording magnetic field is generated in the gap 16 between the upper and lower cores 17 and 15 by applying a recording current to the coil of the induction type magnetic head 3 during recording. Recording on the recording medium is performed by this magnetic field. At the time of reproduction, a sense current flows through the MR film 9 via the electrode films 12 and 13 of the MR head 2 and passes over the track on the magnetic recording medium, thereby increasing the intensity of the magnetic field emitted from the written magnetic information. The voltage at both ends of the MR film 9 is modulated in accordance with this, and reproduced as magnetic information.

Next, the off-track characteristic of the MR head, that is, the change in the reproduction output when the MR head is displaced from the track on the magnetic recording medium will be described.
FIG. 3 is a diagram for explaining reproduction and off-track characteristics by the MR head, and FIG. 3A is a plan view showing a state in which reproduction is performed by the MR head. FIG. 3 (b)
FIG. 3 is a diagram showing off-track characteristics of an MR head.

First, referring to FIG. 3A, the MR head 2 moves when the sensitive portion 20 of the MR film 9 between the electrode films 12 and 13 reaches just above the track 19 recorded on the recording medium. Shows the maximum playback output. When the MR head 2 moves in a direction perpendicular to the moving direction of the recording medium, that is, in the track width direction, the recorded track 19 becomes
The MR head 9 shifts from the position of the sensitive part 20 of the MR film 9 and moves toward the non-sensitive part 21 or the non-sensitive part 22, which is the junction between the MR film 9 and the electrode films 12 and 13. descend.

In FIGS. 3A and 3B, FIG.
In the figure, the direction in which the MR head 2 shifts is indicated by a sign (+) for a rightward shift, and the sign (-) is a shift in the leftward direction.

Next, referring to FIG. 3B, the reproduction output of the MR head 2 reaches a peak value when the center of the MR head is on the track center of the recording medium, and decreases as the MR head 2 deviates from the track center. Characteristics (off-track characteristics). Then, in the off-track characteristic of the MR head, small bumps (output rise) called side lobes occur as shown in the figure.

In order to reduce the side lobe, for example, Japanese Patent Application Laid-Open No. Hei 8-185612 discloses that a non-sensitive portion of an MR film of an MR head is formed to be inclined with respect to a magnetization reversal boundary of a track recording signal. Thus, a technique for reducing the power consumption is disclosed.

[0013]

The occurrence of side lobes, which are the off-track characteristics inherent to the MR head, causes an increase in crosstalk from adjacent tracks. Is an obstacle
There is a drawback that it cannot be used in a magnetic disk device having a high recording density. Further, in the MR head described in Japanese Patent Application Laid-Open No. 8-185612, although the side lobe is reduced, the structure of the MR head is complicated, so that there is a problem that the number of manufacturing steps is increased and the cost is increased.

An object of the present invention is to solve such a problem, and provides an MR head having a small side lobe and a simple structure, and a high recording density magnetic disk drive using the same. It is in.

[0015]

According to the present invention, a lower shield, a lower gap, and a lower gap are formed on a protective film formed on a slider substrate.
An MR element in which an AL bias film, a spacer film, and a magnetoresistive film are sequentially laminated, an antiferromagnetic film and an electrode film are laminated on both sides of the magnetoresistive film, and each is joined to the magnetoresistive film. In, the strength of the exchange coupling magnetic field between the magnetoresistive film and the antiferromagnetic film,
It is not less than 135 Oersted. The MR element is used for an MR head and mounted on a magnetic recording / reproducing apparatus.

According to the present invention, the strength of the exchange coupling magnetic field (Hex) between the MR film and the antiferromagnetic film joined to both ends of the MR film is one.
By setting it to 35 Oe or more, the change in magnetization in the non-sensitive portion of the MR film with respect to the magnetic field from the track recorded on the recording medium becomes small, so that the side lobe can be reduced.

[0017]

Next, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a front view showing one embodiment of the present invention from the side facing a recording medium. In the drawings, the same reference numerals are used for components having the same shape and function as those of the conventional example shown in FIG. Here, the MR head constituting the composite magnetic head will be described.

Referring to FIG. 1, an MR head 2 having a read-only MR element includes an Altic (Al ₂ O ₃ —Ti).
C) on a protective film (such as Al ₂ O ₃ ) formed on a slider substrate 4 made of a ceramic material such as permalloy (Ni).
The lower shield 5 having a thickness of 2 μm using Fe) is formed,
An Al ₂ O film having a thickness of 0.07 μm to form an insulating layer thereon
_The lower gap 6 made of ₃ is laminated. Further, on the lower gap 6, a SAL bias film 7 made of CoZrMo with a thickness of 23 nm, a spacer film 8 made of Ta with a thickness of 10 nm, and a M film made of NiFe with a thickness of 20 nm
An R film 9 is laminated.

On the left and right sides of the MR film 9, antiferromagnetic films 10 and 11 made of NiMn and having a thickness of 50 nm for making the MR film into a single magnetic domain are joined, and Au (gold), W
Electrode films 12 and 13 made of (tungsten) or the like are laminated and joined to the MR film 9. Then, on the MR film 9 and the electrode films 12 and 13, the film thickness of the insulating layer constituting the insulating layer is 0.1 mm.
An upper gap 14 made of Al ₂ O ₃ having a thickness of 09 μm is formed, and an upper shield 15 made of NiFe having a thickness of 3 μm is formed thereon.

Next, the side lobe of the off-track characteristic in the MR head thus configured (see FIG. 3B) and the exchange coupling magnetic field between the MR film 9 and the antiferromagnetic films 10 and 11 (see FIG. Hex) will be described. Here, the size of the side lobe is defined by the ratio of the output Vside of the side lobe to the maximum value Vmax of the output (indicated by Vside / Vmax × 100 [%]).

FIG. 4 is a view for explaining the side lobe of the off-track characteristic and the exchange coupling magnetic field (Hex) between the MR film and the antiferromagnetic film in the MR head of the present invention.
The strength of the exchange coupling magnetic field (Hex) between the MR film and the antiferromagnetic film is set by controlling crystal growth during the formation of the antiferromagnetic film.

Referring to FIG. 4, as the exchange coupling magnetic field increases, both the size (average value) of the side lobe and the failure rate when the standard is set to 3% or less decrease, and the strength of the exchange coupling magnetic field decreases. It can be seen that the defect rate becomes 0% when the value exceeds 135 Oe.

[0024]

As described above, according to the present invention, M
The exchange coupling magnetic field strength between the R film and the antiferromagnetic film is 135
By setting it to Oersted or higher, side lobes, which are the off-track characteristics inherent to MR heads, are reduced, and crosstalk from adjacent tracks is reduced, thus realizing an MR head with a simplified structure and reduced cost. This makes it possible to provide a magnetic disk device having a high recording density.

[Brief description of the drawings]

FIG. 1 is a front view illustrating an embodiment of the present invention as viewed from a surface facing a recording medium.

FIG. 2 is a front view showing an example of a conventional composite magnetic head from a recording medium facing surface.

FIG. 3 is a diagram illustrating reproduction and off-track characteristics by an MR head.

FIG. 4 is a diagram for explaining the relationship between the side lobe of off-track characteristics and the exchange coupling magnetic field (Hex) between the MR film and the antiferromagnetic film in the MR head of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Composite magnetic head 2 MR head 3 Inductive magnetic head 4 Slider substrate 5 Lower shield 6 Lower gap 7 SAL bias film 8 Spacer film 9 MR film 10,11 Antiferromagnetic film 12,13 Electrode film 14 Upper gap 15 Upper shield Reference Signs List 16 Write gap 17 Upper core 18 Protective film 19 Track recorded 20 Sensitive part 21, 22 Non-sensitive part

Claims (3)

[Claims] 1. A protective film formed on a slider substrate,
A lower shield, a lower gap, a SAL bias film, a spacer film, and a magnetoresistive film are sequentially laminated, and an antiferromagnetic film and an electrode film are laminated on both sides of the magnetoresistive film. A magnetoresistive element having a junction, wherein an exchange coupling magnetic field between the magnetoresistive film and the antiferromagnetic film has a strength of 135 Oe or more. 2. A magneto-resistance effect type magnetic head using the magneto-resistance effect element according to claim 1. 3. A magnetic recording / reproducing apparatus comprising the magnetoresistive head according to claim 2.