JP2541084B2 - Thin film magnetic head - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film magnetic head for writing or reading information on a magnetic recording medium.

[0002]

2. Description of the Related Art In recent years, magnetic recording devices such as rigid magnetic disk devices for computers, flexible magnetic disk devices, magnetic tape devices, etc. have been made higher in recording density. Therefore, a thin film magnetic head in which a magnetic pole, which has been conventionally formed of a bulk magnetic material, is formed of a magnetic thin film has been developed and widely used. Figure 10 shows the thin film magnetic head.
FIG. In the figure, 11 is the substrate and 12 is the bottom
Part magnetic pole, 13 magnetic gap, 15 winding, 16 upper part
It is a magnetic pole. The lower part made of a high magnetic permeability soft magnetic film on the substrate 11.
A partial magnetic pole 12 is formed and formed on the lower magnetic pole 12.
One end contacts one end of the lower magnetic pole and the other end contacts the lower magnetic pole.
The other end of 12 is opposed via a magnetic gap 13,
Part of the magnetic pole 12 and the magnetic gap 13
An upper magnetic pole 16 forming a magnetic circuit is formed. under
The magnetic circuit passes between the partial magnetic pole 12 and the upper magnetic pole 16 and
A winding portion 15 is formed to form a coil having a predetermined number of turns intersecting with each other.
Between the winding portions 15 and between the winding portion 15 and the upper magnet.
Interlayer insulating film 1 for electrically insulating the pole 16 from the bottom pole 12
4 and. The width of the track written on the recording medium by the thin film magnetic head is defined by the width of the tip of the magnetic pole pattern. In order to increase the recording density, it is necessary to reduce the width of the tip of the magnetic pole pattern to reduce the width of the track in which information is written, and to reduce the interval between tracks to be written (track pitch 7). To be done. As such narrowing of tracks and narrowing of track pitches progress, more accurate positioning of the head during read operation is required, and when off-track occurs during read operation, the influence of adjacent tracks is reduced. However, there arises a problem that it becomes difficult to accurately read the information. Therefore, in order to secure a head positioning margin during a read operation, a so-called wide write narrow read method has been considered in which a width 5 for reading information is set smaller than a width 4 of a written track. FIG. 3 is a diagram for explaining the wide write / narrow read method. One method of realizing this method is to design the write head and the read head separately and optimize the width of each magnetic pole pattern.

Another method for realizing the wide write / narrow read system while performing the write operation and the read operation with the same head is to form a low magnetic permeability region at a part of both ends of the magnetic pole. In a thin-film magnetic head having such a structure, when excited by a magnetic field large enough to saturate the magnetic pole, the magnetization changes in the entire range of the magnetic pole pattern width, but a magnetic field smaller than the saturation magnetic field of the magnetic pole. When excited by, the low magnetic permeability regions at both ends of the magnetic pole are present as magnetization immovable regions and do not contribute to the magnetization change. Therefore, it is possible to form recording tracks over the entire range of the magnetic pole pattern width during the write operation, and then perform the read operation with the same head with a width narrower than the written width. Conventionally, as a method of forming a low magnetic permeability area, a method of laminating a hard magnetic film, an antiferromagnetic material film, or a ferrimagnetic material film on predetermined areas at both ends of a magnetic pole, and a method of making a predetermined area hard magnetic by ion implantation Have been proposed (for example, Japanese Patent Application No. 3-142188).
FIG. 4 is a diagram for explaining a conventional thin film magnetic head in which a low magnetic permeability region is formed by laminating hard magnetic films 9 on both ends of a magnetic pole. FIG. 5 is a diagram for explaining a conventional thin film magnetic head in which the low magnetic permeability region 10 is formed by ion implantation on both ends of the magnetic pole.

[0004]

In the former method, the write head and the read head are designed separately,
When this is used as a composite type head, there is a drawback that a great burden is placed on the manufacturing process, such as the need to accurately align the magnetic pole patterns. Also,
The latter method has drawbacks such that it is difficult to position a predetermined region when the low magnetic permeability region is provided in the narrow portion at both ends of the magnetic pole, and the manufacturing process is complicated.

An object of the present invention is to provide a thin film magnetic head capable of realizing an ideal wide write / narrow read system without complicating the manufacturing process while performing the write operation and the read operation by the same head. Especially.

[0006]

A thin film magnetic head according to the present invention comprises a magnetic pole made of a high magnetic permeability soft magnetic film, and recording and magnetic flux detection windings arranged close to the magnetic pole.
It is characterized in that the magnetic pole is composed of a magnetic multilayer film in which a first layer which is a soft magnetic film having uniaxial magnetic anisotropy and a second layer which is a non-magnetic film are alternately laminated. Further, a soft magnetic film having a periodic structure formed by repeating a plurality of ferromagnetic materials is used for the first layer.

[0007]

When the magnetic pole of the thin-film magnetic head is composed of the magnetic multilayer film, magnetostatic coupling works between the magnetic layers via the non-magnetic layer,
Low magnetic permeability regions are formed at both ends of the magnetic pole for pinning of magnetization. The width of this low-permeability region can be controlled by selecting the layer thickness of the first layer and the second layer, or the anisotropic magnetic field HK of the first layer and the magnitude of the saturation magnetization MS. As a result, the read width can be designed to have an optimum value with respect to the write width.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. Example 1 FIG. 1 is a diagram showing the results of observing the magnitude of the change in magnetization of the magnetic pole portion of the thin film magnetic head of the first example of the present invention using a Kerr effect microscope.

In the first embodiment, an electron beam vacuum evaporation apparatus having two evaporation sources is used to form a NiFe layer forming the first layer and a V layer forming the second layer. NiFe / fabricated by stacking alternately and continuously
The V multilayer film was patterned into a magnetic pole shape (magnetic pole pattern width 3 μm) by ion milling. The thickness of the NiFe layer was controlled to 50 nm and the thickness of the V layer was controlled to 20 nm by changing the opening / closing time of the shutter provided directly above each evaporation source. At this time, the magnitude of the anisotropic magnetic field Hk of the magnetic layer (NiFe layer) is 6 Oe, and the magnitude of the saturation magnetization M _S is 800 Gauss.
Met. When excited by a magnetic field of 200 Oe (10 MHz), the magnetization changed in the entire range of the magnetic pole pattern width. It existed as a region and did not contribute to the change in magnetization. As a result, a thin film magnetic head was realized in which the write operation was performed with a width of 3 μm and the read operation was performed with a width of 1 μm.

In this multilayer structure, the magnetic layer (Ni
Fe layer), non-magnetic layer (V layer) thickness, magnetic layer (N
iFe layer) various N with different magnitude of anisotropic magnetic field HK
The results of observing the magnitude of the change in magnetization under the above conditions using an Kerr effect microscope are shown in FIG.
These are shown in FIGS. 7 and 8, respectively. By selecting the thickness of each layer or the anisotropic magnetic field HK, the read width can be designed to have an optimum value with respect to the write width. Example 2 FIG. 2 is a diagram showing the results of observing the magnitude of the change in magnetization of the magnetic pole portion of the thin film magnetic head of the second example of the present invention using a Kerr effect microscope.

In the second embodiment, a Fe layer and a Ni layer are formed by using an electron beam vacuum evaporation system equipped with three evaporation sources.
Fe / Fe forming the first layer in which Fe layers are alternately laminated
It was produced by alternately and continuously laminating a NiFe layer and a V layer forming a second layer (Fe / NiFe) /
The V multilayer film was patterned into a magnetic pole shape (magnetic pole pattern width 3 μm) by ion milling. By changing the opening / closing time of the shutter installed directly above each evaporation source, Fe / Ni
Fe layer (stacking period 10 nm, Fe layer thickness = NiFe layer thickness =
The thickness of the V layer was controlled to 50 nm, and the thickness of the V layer was controlled to 20 nm. At this time, the magnitude of the anisotropic magnetic field Hk of the magnetic layer (Fe / NiFe layer) was 6 Oe, and the magnitude of the saturation magnetization Ms was 1200 Gauss. 200 Oe (10 MH
In the case of excitation with the magnetic field of z), the magnetization change occurred in the region over the entire range of the magnetic pole pattern width.
1.25 μm at both ends of the magnetic pole when excited by a magnetic field of (Hz)
The region of exists as a stationary region of magnetization and did not contribute to the change of magnetization. As a result, a thin film magnetic head was realized in which the write operation was performed with a width of 3 μm and the read operation was performed with a width of 0.5 μm.

In this multilayer structure, the Fe layer and N
By changing the layer thickness ratio of the iFe layer, the magnetic layer (Fe / NiFe
(Fe / N) in which the magnitude of the saturation magnetization MS of the layer is changed.
FIG. 9 shows the result of observing the magnitude of the change in magnetization under the above-mentioned conditions using an Kerr effect microscope after forming an iFe) / V multilayer film.
Shown in By selecting the magnitude of the saturation magnetization MS, the read width can be designed to have an optimum value with respect to the write width.

The present invention can be applied not only to the conventional thin film magnetic head described above, but also to the main magnetic pole portion of a single magnetic pole type vertical magnetic head, and is applicable to future high density and high sensitivity magnetic heads. It brings a beneficial effect in practical application.

[0014]

As described above, according to the present invention, the write operation and the read operation are performed by the same head, but the manufacturing process is not complicated.
It is possible to provide a thin film magnetic head capable of realizing an ideal wide write narrow read system. Also, the layer thickness of the first layer and the second layer, or the anisotropic magnetic field H of the first layer
By selecting K and the magnitude of the saturation magnetization MS, the read width can be designed to have an optimum value with respect to the write width.

[Brief description of drawings]

FIG. 1 is a diagram showing a result of observing the magnitude of a change in magnetization of a magnetic pole portion of a thin film magnetic head according to a first embodiment of the present invention using a Kerr effect microscope.

FIG. 2 is a diagram showing a result of observing a magnitude of a change in magnetization of a magnetic pole portion of a thin film magnetic head of a second embodiment of the present invention using a Kerr effect microscope.

FIG. 3 is a diagram illustrating a wide write / narrow read system.

FIG. 4 is a diagram illustrating a conventional thin film magnetic head in which a low magnetic permeability region is formed by laminating hard magnetic films on both ends of a magnetic pole.

FIG. 5 is a diagram illustrating a conventional thin film magnetic head in which a low magnetic permeability region is formed by ion implantation in a part of both ends of a magnetic pole.

FIG. 6 is an observation of the magnitude of the change in magnetization of the magnetic pole portion when the thickness of the magnetic layer (NiFe layer) is changed in the thin film magnetic head of the first embodiment of the present invention using a Kerr effect microscope. It is a figure which shows the result.

FIG. 7 is a graph showing the magnitude of the change in magnetization of the magnetic pole portion when the thickness of the non-magnetic layer (V layer) is changed in the thin film magnetic head of the first embodiment of the present invention by using a Kerr effect microscope. It is a figure which shows the result of observation.

FIG. 8 shows the magnitude of the change in magnetization of the magnetic pole portion when the magnitude of the anisotropic magnetic field H K of the magnetic layer (NiFe layer) is changed in the thin film magnetic head of the first embodiment of the present invention. It is a figure which shows the result observed using the Kerr effect microscope.

FIG. 9 is a graph showing the magnitude of change in magnetization of the magnetic pole portion when the magnitude of the saturation magnetic field M S of the magnetic layer (Fe / NiFe layer) is changed in the thin film magnetic head of the second embodiment of the present invention. It is a figure which shows the result observed using the Kerr effect microscope.

FIG. 10 Diagram showing the overall structure of a conventional thin-film magnetic head
Is.

[Description of Reference Signs] 1 magnetic pole 2 NiFe layer 3 V layer 4 write track width 5 read track width 6 Fe layer 7 track pitch 8 adjacent track 9 hard magnetic film 10 ion implantation region 11 substrate 12 lower magnetic pole 13 magnetic gap 14 interlayer insulating film 15 winding part 16 upper magnetic pole

Claims (2)

(57) [Claims] 1. A lower magnetic pole composed of a high magnetic permeability soft magnetic film,
One end of the lower magnetic pole is formed on the lower magnetic pole.
And the other end through the magnetic gap to the other end of the lower magnetic pole.
Facing each other, and part of the magnetic gap together with the lower magnetic pole.
An upper magnetic pole forming a magnetic circuit having:
Where it passes between the magnetic pole and the upper magnetic pole and intersects with the magnetic circuit.
Between the winding parts that form a constant number of coils and between the winding parts and
Electrically insulate the winding part from the upper magnetic pole and the lower magnetic pole.
And an interlayer insulating film for
A thin-film magnetic head having low-permeability regions at both ends in the track width direction of at least one of the poles, wherein the magnetic pole is a soft magnetic film having uniaxial magnetic anisotropy.
Layer and the second layer, which is a non-magnetic film, form the magnetic gap.
A thin film magnetic head comprising a magnetic multi-layered film which is alternately laminated in parallel with a layer to be formed . 2. The thin-film magnetic head according to claim 1, wherein a soft magnetic film having a periodic structure formed by repeating a plurality of ferromagnetic bodies is used for the first layer.