JP2001284154A - Method of manufacturing cobalt-iron-nickel magnetic film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a cobalt-iron-nickel magnetic film having high magnetic permeability. SOLUTION: The cobalt-iron-nickel magnetic film 10 is formed through magnetic field-applied plating and magnetic field-applied heat-treated by rotating the film 10, while a magnetic field is applied in the in-plane direction of the film 10. Alternatively, the film 10 is formed by magnetic field-applied plating and magnetic field-applied heat-treated by impressing a magnetic field from the direction, in which the anisotropy of the film 10 becomes an axis of hard magnetization.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head of a magnetic disk drive which is one of external storage devices of a computer, and a magnetic material of a magnetic recording medium. The present invention relates to a method for producing a film.

[0002] In recent years, iron-cobalt based magnetic films have a high saturation magnetic flux density (Bs) and can be used as a magnetic pole material for a thin-film magnetic head for a high coercive force (Hc) medium capable of increasing the recording density. , Research and development are underway.

On the medium side, the medium has a two-layer structure of a perpendicular recording layer for recording signals by forming residual magnetization in the thickness direction of the medium and a backing magnetic layer below the layer for returning magnetic flux. The use of a perpendicular double-layered medium as a backing magnetic layer has also been reported.

[0004]

2. Description of the Related Art As a means for forming an iron-cobalt magnetic film, there are a plating method, a sputtering method and the like. In the plating method, the iron: cobalt ion ratio is 1: 5 to 1:30 by making the bath composition, saturation magnetic flux density (Bs) is 15000Gauss or more,
It has been reported that a surface with low surface roughness (glossy surface) can be obtained (Japanese Patent Application No. 2-081809).

[0005]

However, the iron having the above structure
-Cobalt magnetic films have a problem of poor corrosion resistance. That is, the value of the pitting potential (potential at which pits are generated) obtained from the spontaneous polarization measurement method (the potential is raised to the + side from the natural electrode potential of the membrane and the anode polarization curve is measured) is -190 to -190. As low as 260mV,
When an iron-cobalt based magnetic film is used for the magnetic pole of the head, there is a problem that corrosion and deterioration of characteristics are caused.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for producing a cobalt-iron-nickel magnetic film having high magnetic permeability.

[0007]

According to a first aspect of the present invention, a cobalt-iron-nickel magnetic film is formed by plating in a magnetic field, and then a magnetic field is applied in the in-plane direction of the film. It rotates while applying heat and performs heat treatment in a magnetic field. According to a second aspect of the present invention, the applied magnetic field of the first aspect is 200 Oe
As above, the rotation speed is 30 to 80 rpm, the heat treatment temperature is 200 to 300 ° C
It is characterized by being.

According to the present invention, by rotating while applying a magnetic field in the in-plane direction of the film and performing heat treatment in the magnetic field, the magnetic anisotropy is disturbed and a magnetic film having a magnetic permeability of 1300 or more can be obtained.

The invention according to claim 3 is characterized in that cobalt-iron-
A nickel magnetic film is formed by plating in a magnetic field, and heat treatment is performed in a magnetic field while applying a magnetic field from a direction in which the anisotropy of the magnetic film is a difficult axis. The invention according to claim 4 is characterized in that the heat treatment temperature in claim 3 is 200 to 300 ° C. and the heat treatment time is 1 hour or more.

According to the present invention, a magnetic field is applied from a direction in which the magnetic anisotropy of the magnetic film becomes a hard axis, and heat treatment is performed to disturb the magnetic anisotropy and form a magnetic film having a magnetic permeability of 1300 or more. Obtainable.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. First, a cobalt-iron-nickel magnetic film will be described with reference to FIGS. FIG. 1 is a view showing the film composition of a sample 10. In this sample 10, 1 is a glass substrate, and 2 is titanium (Ti) formed on the glass substrate 1.
Layer 3 is nickel (Ni) -iron (F) formed on titanium layer 2.
e) Layer 4 is a cobalt (Co) -iron (Fe) -nickel (Ni) layer formed on the nickel-iron layer 3 in a plating bath.

When the cobalt-iron-nickel layer 4 was formed in a unidirectional magnetic field under the plating bath composition shown in FIG. 2 and the plating conditions shown in FIG. 3, the results shown in FIG. 4 were obtained. Was. Here, FIG. 4 is a diagram showing the saturation magnetic flux density and the pitting potential at each weight% of the film composition. In FIG. 4, the pitting potential is 0 m
If it is V or more, corrosion resistance can be secured. In addition, it is sufficient that the saturation magnetic flux density (Bs) can be secured to 14 kgauss or more.

The inventors of the present invention have conducted experiments under these conditions, and as a result, it has been found that under the following conditions, the above-mentioned pitting potential and saturation magnetic flux density are satisfied.

Ion ratio of plating bath Cobalt: iron: nickel = 4 to 13: 1 to 4:24 to 42% by weight of plating film Cobalt content: 38 to 65% by weight, iron content: 10 to 31% by weight With such a composition, a cobalt-iron-nickel magnetic film having good corrosion resistance can be obtained without sacrificing the saturation magnetic flux density.

Next, referring to FIG. 5 to FIG.
Embodiments according to the inventions described in 4 to 4 will be described. Here, FIG. 5 is an explanatory view of an embodiment of the first and second aspects of the present invention, and FIG.
FIG. 4 is an explanatory view of an embodiment of the invention described in claims 3 and 4.

A sample 10 formed using a plating bath having a composition as shown in FIG. 7 was subjected to a heat treatment in a magnetic field under the following conditions. Heating temperature: 200 ° C Heating time: 1 hour Applied magnetic field: 200 Oe, 800 Oe At this time, the direction of the applied magnetic field was set as the following parameters.

As shown in FIG. 5, the sample is rotated by applying a magnetic field in an in-plane direction. As shown in FIG. 6, a magnetic field is applied in the easy axis direction of the in-plane magnetic anisotropy. As shown in FIG. 6, a magnetic field is applied in the hard axis direction of in-plane magnetic anisotropy.

Here, the easy axis and the difficult axis will be described. FIG. 9 is a diagram showing the magnetization characteristics of the sample 10 in the A direction in FIG. 8. In this case, when the magnetic field (magnetic field strength) is increased and applied above a certain magnetic field, the direction of the magnetization is reversed. . A direction exhibiting such characteristics is called an easy magnetic direction (easy axis).

On the other hand, FIG. 10 is a diagram showing the magnetization characteristics of the sample 10 in the direction B in FIG. 8. In this case, as the magnetic field (magnetic field strength) is increased, the magnetization direction is Gradually reverses. This is the direction of hard magnetization
(Difficult axis).

FIGS. 11 and 12 show an applied magnetic field of 2000, respectively.
7 shows the relationship between the magnetic permeability and the saturation magnetic flux density depending on the application direction of the heat treatment at e and 8000 e. As can be seen from FIGS. 11 and 12, the magnetic permeability during film formation is about 800,
By performing the rotating magnetic field heat treatment (), the magnetic permeability can be increased to about 1300.

When the heat treatment is applied from the hard axis, the direction of anisotropy is reversed, but the magnetic permeability can be increased to about 1300. However, when applied from the easy axis,
When the heat treatment () is performed, on the contrary, the magnetic permeability decreases to 600.

As can be seen from FIGS. 11 and 12, no difference was observed between the applied magnetic field of 200 Oe and 800 Oe. or,
The saturation magnetic flux density hardly changed even after the heat treatment (Bs ≒ 17000 Gauss).

FIG. 13 shows the relationship between the magnetic permeability and the saturation magnetic flux density depending on the heat treatment time. In the case of heat treatment in a rotating magnetic field, the heat treatment was performed with various heat treatment times (0 to 6 hours). I have. Here, other heat treatment conditions are the same as those in FIGS.

When the target value of the magnetic permeability is set to 1300, the heat treatment is performed.
By performing the treatment for one hour, a magnetic permeability of ≒ 1300 can be obtained.
Further, as the time is increased, the magnetic permeability tends to gradually increase. For example, when performed for 6 hours, the magnetic permeability is 1500
About. The saturation magnetic flux density is almost the same as in FIGS. 11 and 12.

[0025]

As described above, according to the present invention, the following effects can be obtained. By rotating while applying a magnetic field in the in-plane direction of the film, and performing a heat treatment in a magnetic field, the magnetic anisotropy is disturbed, and the magnetic permeability becomes 13
More than 00 magnetic films can be obtained.

By applying a magnetic field from a direction in which the magnetic anisotropy of the magnetic film is a difficult axis and performing a heat treatment, the magnetic anisotropy is disturbed and a magnetic film having a magnetic permeability of 1300 or more can be obtained. .

[Brief description of the drawings]

FIG. 1 is a cross-sectional configuration diagram showing a film composition of a sample of a cobalt-iron-nickel magnetic film.

FIG. 2 is a diagram illustrating the composition of a plating bath.

FIG. 3 is a diagram illustrating plating conditions.

FIG. 4 is a diagram showing a saturation magnetic flux density and a pitting potential at each weight% of a film composition.

FIG. 5 is an explanatory diagram of an embodiment of the invention described in claims 1 and 2;

FIG. 6 is an explanatory view of an embodiment according to the third and fourth aspects of the present invention.

FIG. 7 is a diagram illustrating the composition of a plating bath according to an embodiment of the present invention.

FIG. 8 is a view for explaining the anisotropy of a magnetic film formed according to the embodiment of the present invention.

FIG. 9 is a diagram illustrating magnetization characteristics in an A direction in FIG. 8;

FIG. 10 is a diagram illustrating magnetization characteristics in a B direction in FIG. 8;

FIG. 11 is a diagram illustrating the relationship between magnetic permeability and saturation magnetic flux density depending on the application direction of heat treatment in the case of an applied magnetic field of 200 Oe.

FIG. 12 is a diagram illustrating the relationship between the magnetic permeability and the saturation magnetic flux density depending on the application direction of the heat treatment in the case of an applied magnetic field of 800 Oe.

FIG. 13 is a diagram illustrating the relationship between magnetic permeability and saturation magnetic flux density depending on heat treatment time.

[Description of Signs] 1 glass substrate 2 titanium layer 3 nickel-iron layer 4 cobalt-iron-nickel layer 10 samples

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Shinichi Tanaka, Inventor 4-1-1 Kamikadanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Mitsumasa Oshiki 4-1-1 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa No. 1 Inside Fujitsu Limited (72) Inventor Kunio Iijima 4-1-1 Kamikadanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Inside Fujitsu Limited

Claims (4)

[Claims] 1. A cobalt-iron-nickel magnetic film is formed by a plating method in a magnetic field, and is then rotated while applying a magnetic field in an in-plane direction to perform a heat treatment in a magnetic field. A method for producing a cobalt-iron-nickel magnetic film. 2. The manufacturing method according to claim 1, wherein the applied magnetic field is 200 Oe or more, the rotation speed is 30 to 80 rpm, and the heat treatment temperature is 200 to 300 ° C. Method. 3. A method of forming a cobalt-iron-nickel magnetic film by a plating method in a magnetic field, and performing a heat treatment in a magnetic field while applying a magnetic field from a direction in which the anisotropy of the magnetic film is a difficult axis. A method for producing a cobalt-iron-nickel magnetic film, comprising: 4. The method for producing a cobalt-iron-nickel magnetic film according to claim 3, wherein the heat treatment temperature is 200 to 300 ° C., and the heat treatment time is 1 hour or more.