JPH03108111A - Magnetic film core for thin-film magnetic head and production thereof - Google Patents

Abstract

PURPOSE:To obtain the good magnetic film core for the thin-film magnetic head even if the width of a magnetic path is narrowed by sticking 2nd magnetic films having the magnetic anisotropy stronger than the magnetic anisotropy of a 1st magnetic film at both ends in the direction intersecting with the magnetic path direction of the 1st magnetic film. CONSTITUTION:The 1st magnetic film 5 is formed by an electroplating in a magnetic field on a metallic film 2 for electrodes erected with a resist 1 for a frame. Alumina 6 for a cover is formed in the part enclosed with the resist 1 for the frame on the 1st magnetic film 5 and thereafter, the magnetic film 5, resist 1, metallic film 2 and thin film 3 exclusive of the films covered with the alumina 6 are removed. The 2nd magnetic film 7 is stuck by an electroplating method on both side surfaces of the 1st magnetic film 5. Further, the alumina 6 for the cover is removed and the 1st and 2nd magnetic films 5 and 7 are heat treated to enhance the matching property. The good magnetic film core for the thin-film magnetic head is obtd. even if the magnetic path width is narrowed for the purpose of high-density recording in such a manner.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic film core for a thin film magnetic head suitable for high-density magnetic recording and a method for manufacturing the same.

[Conventional technology]

In recent years, thin-film magnetic heads, which are manufactured by laminating magnetic films with magnetic anisotropy and forming patterns using lithography technology, have been developed and used as recording heads suitable for high-density recording in computer hard disks. ing.

FIG. 8 is a plan view of a thin film magnetic head using a magnetic film, and has a structure in which a coil 9 is wound around a funnel-shaped magnetic film core 8 (see Japanese Patent Laid-Open No. 175212/1983).

The magnetic path width T of the lower portion of the magnetic film core 8 near the recording medium facing surface 10. The dimensions are made narrow in accordance with the recording track width. Therefore, as recording density increases, the magnetic path width T increases.

It becomes necessary to make it narrower.

Further, the magnetic film used in the thin film magnetic head needs to have high magnetic permeability in a high frequency range. The magnetic film has uniaxial magnetic anisotropy, and the magnetic permeability at high frequencies is higher in the direction of the axis of hard magnetization than in the direction of the axis of easy magnetization. This is because most of the magnetization in the film is oriented in the direction of the easy axis of magnetization, and therefore, during the magnetization process in the direction of the hard axis, magnetization phenomena mainly occur due to magnetization rotation with fast response in the high frequency range. Therefore, the direction of the axis of hard magnetization of the magnetic film is made to coincide with the direction of the magnetic path, and the direction of the axis of easy magnetization is set to the magnetic path width T. It is common practice to match the

Incidentally, the energy that determines the magnetic domain structure in a magnetic film consists of magnetostatic energy, domain wall energy, magnetic anisotropy energy, magnetoelastic energy, and the like. FIG. 9 is a schematic diagram showing the magnetic domain structure of the magnetic film core. The magnetic domain of the magnetic film core is the hexagonal magnetic domain 1 in the center of the figure, with magnetization oriented in the easy axis direction.
4.14... and triangular magnetic domains 13.13... that occur at both ends and whose magnetization is oriented in the direction of the hard-to-magnetize magnetic domain. The triangular magnetic domains 13, 13, . Here, since the magnetization in the triangular magnetic domain is oriented in the direction of the hard axis, the magnetization process in the direction of the hard axis causes domain wall movement, which has a slow response in the high frequency range, and This causes a decrease in magnetic permeability in the high frequency range. Also, the size of the magnetic domain is mainly determined by the domain wall energy and the magnetic anisotropy energy of the triangular magnetic domains 13, 13..., and the magnetic path width T for high-density recording. If it becomes narrower, the proportion of the triangular magnetic domains 13, 13, . . . in the film increases, and the magnetic permeability of the magnetic film at high frequencies decreases.

On the other hand, the magnetic permeability μ of the hard-to-magnetize magnetic domain is the saturation magnetic field B.

can be approximated to the value divided by the magnetic anisotropy field HK (μ#B, /l(x).In other words, in order to increase the magnetic permeability, the magnetic anisotropy field H8 of the magnetic film can be reduced. Good. However, if the magnetic anisotropy of the magnetic film is made too small, the area occupied by the triangular magnetic domains 13, 13, etc. will increase, and the magnetic permeability at high frequencies will decrease.

In particular, when the magnetic path width T1 is narrowed for high-density recording, the ratio of triangular magnetic domains in the magnetic film increases, resulting in a decrease in magnetic permeability in the high frequency range and a problem in that the recording and reproducing efficiency of the magnetic head deteriorates. was there.

Conventionally, as a way to improve this problem, thin-film magnetic heads have been proposed in which the strength of magnetic anisotropy is optimized at different portions of the magnetic path width of the magnetic film core to obtain as high magnetic permeability as possible ( Japanese Patent Publication No. 63175212).

[Problem to be solved by the invention]

However, in the thin film magnetic head configured as described above, the magnetic path width T
1. When l is narrowed, the optimum strength of magnetic anisotropy is determined by the magnetic path width T. is stronger than when the magnetic path width T is wide.
. There was a problem in that the magnetic permeability in the direction of the hard-to-magnetize magnetic domain in the hexagonal magnetic domain was lower than that in the case where the hexagonal magnetic domain was wide.

In addition, when a method is used in which the magnetic film is divided into multiple parts and materials with different magnetic anisotropy are separately deposited using sputtering, gaps or steps are created at the boundaries of each part, resulting in poor product quality. was there.

Furthermore, the method of forming a magnetic film by sputtering is not suitable for mass production.

The present invention has been made in view of the above circumstances, and includes a first magnetic film having magnetic anisotropy having stronger magnetic anisotropy than the first magnetic film at both ends in a direction crossing the magnetic path direction. After depositing a second magnetic film having a magnetic field by electroplating, heat treatment is performed in a magnetic field to reduce the area occupied by the triangular magnetic domains in the film without increasing the magnetic anisotropy in the center of the magnetic film. To provide a magnetic film core for a thin film magnetic head which has good magnetic permeability even when the magnetic path width is narrowed for high-density recording by reducing the ratio, and a method for manufacturing the same with mass productivity and good quality. is its purpose.

(Means for Solving the Problems) A magnetic film core for a thin film magnetic head according to the present invention is a thin film magnetic head using a first magnetic film having magnetic anisotropy. A second magnetic film having a stronger magnetic anisotropy than the first magnetic film is attached to both ends in a direction intersecting the direction of the magnetic field.

Further, in the method for manufacturing a magnetic film core for a thin film magnetic head according to the present invention, a second magnetic film having stronger magnetic anisotropy than the first magnetic film is provided at both ends of the first magnetic film in a direction intersecting the magnetic path direction. [Function] The magnetic film core for a thin film magnetic head according to the present invention is characterized in that after the second magnetic film is attached by electroplating, heat treatment is performed in a magnetic field. Since the second magnetic film, which has a stronger magnetic anisotropy than the first magnetic film, is attached to both ends in the direction crossing the direction, the magnetic anisotropy of the first magnetic film is not strengthened. , that is, without reducing the magnetic permeability of the first magnetic film.
It is possible to reduce the proportion of triangular magnetic domains occurring in the vicinity of both ends in the film.

Further, in the method for manufacturing a magnetic film core for a thin film magnetic head according to the present invention, a first magnetic film and a second magnetic film are attached by electroplating, and then heat treatment is performed in a magnetic field. As a result, no gap or step is formed at the boundary between the first magnetic film and the second magnetic film, and high-quality products can be mass-produced.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on drawings showing embodiments thereof.

Fig. 1 is a schematic diagram showing the manufacturing process of a magnetic film core for a thin film magnetic head according to the present invention, Fig. 2 is a graph showing the relationship between the composition of the permalloy film as a magnetic film and the magnetostriction constant, and Fig. 3 is a graph showing the relationship between the composition of the permalloy film as a magnetic film and the magnetostriction constant.
-Magnetic domain structure of permalloy film with t%Ni composition, Figure 4 shows 8
This is the magnetic domain structure of a permalloy film with a 2-1% Ni composition.

In FIG. 12, the vertical axis shows the magnetostriction constant, and the horizontal axis shows the composition (Niwt%) of the permalloy film.

As is clear from the figure, the permalloy film with a high Ni composition has a small magnetostriction constant. Magnetic anisotropy includes magnetocrystalline anisotropy, v
There are J-induced magnetic force anisotropy, stress-induced magnetic anisotropy, and shape magnetic anisotropy. Since tensile stress is acting in the film in the direction of the magnetic path indicated by the arrow in Figure 3, in the region where the magnetostriction constant is negative, the film with a large absolute value of the magnetostriction constant will be forced to move in the direction that intersects the direction of the magnetic path. produces strong stress-induced magnetic anisotropy. A film with a higher Ni composition, that is, a film with a smaller magnetostriction constant, has stronger stress-induced magnetic anisotropy. Therefore, a film with a high Ni composition of 81 wt % or more has strong stress-induced magnetic anisotropy, and the proportion of triangular magnetic domains in the film is small. On the other hand, films with a low Ni composition, that is, films with a negative magnetostriction constant and a small absolute value, have weak stress-induced magnetic anisotropy, so the proportion of triangular magnetic domains in the film is large.

In this example, 82-t%Nf was used as the first magnetic film.
A permalloy film with a composition of 84 wt % Ni, which has stronger magnetic anisotropy than the first magnetic film, is used as a second magnetic film to form a magnetic film for a thin film magnetic head of the present invention in the manufacturing process as shown below. A membrane core was prepared.

The manufacturing process of a magnetic film core for a thin film magnetic head according to the present invention will be explained below with reference to FIG.

First, a Ti thin film 3 for adhesion is placed on an alumina coated TiC substrate 4.
Further, an electrode metal film 2 is formed thereon.

A frame resist 1 is placed on the edge of the magnetic film on the electrode metal film 2 by the frame plating method disclosed in JP-A-50-95147 to form a pattern (FIG. 1(a)). . Here, the shape of the magnetic film is made as shown in FIG. That is, the magnetic path width T corresponds to the recording trunk width of the magnetic film core 8. The conductive path 8 starts from the narrowed part.
Create a shape that looks like a series of letters a. This is because a film with strong magnetic anisotropy, ie, a second magnetic film, is deposited in the subsequent step.

Electrode metal film 2 with frame resist as described above
An 82-t% Ni permalloy film, which is the first magnetic film 5, is formed thereon by electroplating in a magnetic field (Fig. 1(b)).
).

Next, alumina is formed into a film on the first magnetic film 5 by sputtering, and then etched by lithography technology and ion milling using CF4 gas, so that it is surrounded by the frame resist 1 on the first magnetic film 5. A cover alumina 6 is formed on the exposed portion (FIG. 1(C)).

Subsequently, the portions of the first magnetic film 5 not covered by the cover alumina 6 are removed by wet etching, and then the frame resist 1 is removed using an organic solvent. Thereafter, the electrode metal film 2 and the adhesion thin film 3 are removed by ion milling, leaving the portions surrounded by the frame resist 1. Then, a second magnetic film 7 is deposited in a magnetic field by electroplating on both sides of the first magnetic film 5, that is, on the substrate 4 at the portion where the frame resist 1 was formed (the first
Figure (d)).

Furthermore, the cover alumina 6 on the first magnetic film 5 is removed by ion milling. Then, heat treatment is performed in a magnetic field in order to further improve the matching between the first magnetic film 5 and the second magnetic film 7 and to obtain a stable magnetic domain structure (see Fig. 1 (e).
)).

The magnetic domain structure (Fig. 6) of the magnetic film core for a thin film magnetic head of the present invention formed as described above has a structure in which the present invention is not applied even when the magnetic path width T8 is narrowed in order to achieve high-density recording. The area occupied by the triangular magnetic domains can be reduced compared to the magnetic domain structure in the case (FIG. 7).

〔effect〕

As detailed above, the magnetic film core for a thin film magnetic head according to the present invention has stronger magnetic anisotropy than the first magnetic film at both ends in the direction intersecting the magnetic path direction of the first magnetic film. Since the second magnetic film is attached, the proportion of triangular magnetic domains in the film can be reduced without reducing the magnetic permeability of the first magnetic film. As a result, a magnetic film core for a thin film magnetic head with good magnetic permeability can be obtained even when the magnetic path width is narrowed for high-density recording.

Further, in the method for manufacturing a magnetic film core for a thin film magnetic head according to the present invention, a first magnetic film and a second magnetic film are attached by electroplating, and then heat treatment is performed in a magnetic field. As a result, no gap or step is generated at the boundary between the first magnetic film and the second magnetic film, and the present invention has excellent effects such as improving the quality of the product and enabling mass production.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing the manufacturing process of a magnetic film core for a thin film magnetic head according to the present invention, Fig. 2 is a graph showing the relationship between the composition of the permalloy film and the magnetostriction constant, and Fig.
FIG. 4 is a schematic diagram showing the magnetic domain structure of a permalloy film with a composition of 82wt%Ni. FIG. 5 is a schematic diagram showing the magnetic domain structure of a permalloy film with a composition of 82wt%Ni. 6 is a schematic diagram showing the magnetic domain structure of a magnetic film core for a thin film magnetic head according to the present invention, and FIG. 7 is a schematic diagram showing the magnetic domain structure of a magnetic film core for a thin film magnetic head when the present invention is not applied. FIG. 8 is a plan view of a core for a thin film magnetic head using a magnetic film, and FIG. 9 is a schematic diagram showing a magnetic domain structure in the magnetic film.

Claims (1)

[Scope of Claims] 1. In a magnetic film core for a thin film magnetic head using a first magnetic film having magnetic anisotropy, at both ends of the first magnetic film in a direction intersecting the magnetic path direction. A magnetic film core for a thin film magnetic head, characterized in that a second magnetic film having stronger magnetic anisotropy than the first magnetic film is attached. 2. The method for manufacturing a magnetic film core for a thin film magnetic head according to claim 1, wherein both ends of the first magnetic film in a direction intersecting the magnetic path direction have magnetic anisotropy stronger than that of the first magnetic film. 1. A method of manufacturing a magnetic film core for a thin film magnetic head, comprising: depositing a second magnetic film having a second magnetic film by electroplating, and then performing heat treatment in a magnetic field.