JP3113514B2 - Amorphous magnetic alloy thin film and thin film magnetic head using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an amorphous magnetic alloy thin film used as a magnetic core material of a thin film magnetic head.

[0002]

2. Description of the Related Art As a magnetic core material of a thin film magnetic head,
Conventionally, Ni-Fe alloy thin films have often been used. The Ni—Fe alloy thin film has high magnetic permeability and excellent corrosion resistance, but has a problem that it cannot sufficiently cope with high density of magnetic recording because its saturation magnetic flux density is at most about 1.0 T.

As a magnetic alloy thin film having a high saturation magnetic flux density and a high magnetic permeability, Co-Z prepared by a sputtering method is used.
An r-binary amorphous alloy thin film is disclosed in
No. 6,009,045. The Co-Zr alloy thin film is made of Z
In the region where the content of r is about 4.5 atomic% or more, the amorphous state is obtained and excellent soft magnetic characteristics are exhibited. When the Zr content is about 5 atomic%, the saturation magnetic flux density becomes about 1.6T. However, in the composition region where the saturation magnetic flux density is about 1.5 T or more, the substrate does not become amorphous unless the substrate temperature at the time of film formation is about 100 ° C. or less, and the amount of Zr is increased to promote the amorphousization. Then, there is a problem that the saturation magnetic flux density is reduced by about 0.06 T for every 1 atomic% increase.

On the other hand, Japanese Patent Application Laid-Open No. 55-138049 discloses that an amorphous magnetic alloy comprising an iron group element and Zr contains Cr, M
It is disclosed that a third element such as o, W, Ti, V, and Sn is added. However, since the amorphous magnetic alloy disclosed in this publication is a thin ribbon obtained by quenching from a liquid phase, not only is it difficult to use as a magnetic core material of a thin film magnetic head, but also amorphous Since the total content of Zr and the third element needs to be about 8 atomic% or more in order to improve the quality, the saturation magnetic flux density is not so high.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has a high saturation magnetic flux density and excellent heat resistance, and is suitable as a magnetic core material of a thin film magnetic head. The present invention provides a thin magnetic alloy thin film.

[0006]

The amorphous magnetic alloy thin film according to the present invention contains Co, Zr and Sn, and is produced by a gas phase quenching method. The content of Co is 92 atomic% or more, the content of Zr is 4.5 to 6.5 atomic%, and the content of Sn is 0.03%.
Atomic% or more.

[0007]

The present inventor has prepared Co—Zr—Sn alloy thin films of various compositions by sputtering, which is a kind of gas phase quenching method, and the Co—Zr—Sn alloy thin film
We have experimentally found that the coercive force is smaller than the alloy thin film, the specific resistance is large, the film is easily amorphized even at a high temperature, and the tendency of the saturation magnetic flux density to decrease with a decrease in the Co content is small. .

[0008]

Embodiments of the present invention will be described below.

First, FIG. 1 shows the relationship between the coercive force and the Sn content in a Co—Zr—Sn alloy thin film in which the Zr content is constant (5.5 at%).

Here, a DC magnetron type sputtering apparatus was used for film formation, the distance from the target to the substrate was 70 mm, the Ar gas pressure was 6 mTorr, the input power was 1 kW, and the substrate temperature was 100 ° C. Also, in order to improve the magnetic permeability by imparting uniaxial anisotropy to the magnetic alloy thin film,
A permanent magnet is placed close to the substrate and 50
The film was formed while applying a static magnetic field of Oe. When the magnetic alloy thin film is used as a magnetic core material of a thin film magnetic head, the direction in which the static magnetic field is applied is used as a track width direction.

As can be seen from FIG. 1, Co of the Co—Zr alloy thin film (triangular mark) contains only about 0.1 atomic% of Sn.
, The coercive force is significantly reduced, and when the Sn content is increased, the coercive force is further reduced. In addition, among the measurement points (circles) of the Co—Zr—Sn alloy thin film shown in FIG.
When the content of n was quantitatively analyzed precisely, it was 0.03 atomic% Sn.

Next, FIG. 2 shows the relationship between the specific resistance and the Sn content in a Co—Zr—Sn alloy thin film in which the Zr content is constant (5.5 at%).

As can be seen from FIG. 2, the specific resistance increases as the Sn content increases. The magnetic thin film as the magnetic core material of the thin film magnetic head is preferable because the eddy current loss decreases as the specific resistance increases.

Next, a Co-Zr alloy thin film and a Co-Zr-
FIG. 3 shows the relationship between the substrate temperature and the coercive force during film formation of the Sn alloy thin film.

As can be seen from FIG. 3, in the 94.5 atomic% Co-5.5 atomic% Zr alloy thin film (curve A), the coercive force becomes remarkable when the substrate temperature exceeds 100 ° C. This is thought to be due to crystallization. On the other hand, in the 93 atomic% Co-5.5 atomic% Zr-1.5 atomic% Sn alloy thin film (curve B), the substrate temperature during film formation was increased. Exceeds 100 ° C. and reaches 200 ° C., the coercive force has a value of about 0.1 Oe or less, and crystallization is suppressed. If the substrate temperature at the time of film formation can be set high, the adhesion of the film to the substrate is improved, which is advantageous in the method of manufacturing a thin-film magnetic head. The fact that the coercive force does not increase even when the substrate temperature during film formation is high indicates that the crystallization temperature is high and that the heat resistance after film formation is also excellent.

Next, Co-Zr-S having various compositions
FIG. 4 shows a curve connecting compositions in which the saturation magnetic flux densities are equal for the n alloy thin film.

As can be seen from FIG. 4, the iso-saturation magnetic flux density curve swells to the lower Co concentration side as compared with the iso-Co concentration straight line, which indicates that the Co-Zr alloy thin film
This means that the tendency of the saturation magnetic flux density to decrease with a decrease in the content is suppressed by replacing Zr with Sn. The Co-Zr- shown in FIGS.
Even if the Zr content fluctuates within a range of about ± 1% from the Zr content (5.5 atomic%) in the Sn alloy thin film,
, A high saturation magnetic flux density of about 1.4 T or more is obtained.

Next, the effect of improving the corrosion resistance by adding the fourth element to the Co—Zr—Sn alloy thin film will be described.

FIG. 5 shows the results of the salt spray test according to the JIS-Z2317 standard. The horizontal axis represents time, and the vertical axis represents the saturation magnetic flux density normalized by the value of each sample before the salt spray test. It is shown. And curve C (white square mark)
Is 94 atomic% Co-5.5 atomic% Zr-0.5 atomic% S
n alloy thin film, curve D (black triangle) is 93 atomic% Co-
5.5 atomic% Zr-0.5 atomic% Sn-1 atomic% Cr alloy thin film, curve E (solid square) shows 92 atomic% Co-5.5
The test result about the atomic% Zr-0.5 atomic% Sn-2 atomic% Cr alloy thin film is shown.

As can be seen from FIG. 5, Co-Zr-
When Cr is added to the Sn-based alloy thin film, the tendency of the saturation magnetic flux density to decrease in the salt spray test is suppressed.
It means improvement of corrosion resistance by addition.

[0021]

According to the present invention, the magnetic core material of the thin film magnetic head has a high saturation magnetic flux density of about 1.4 T or more, exhibits good soft magnetic characteristics even when the substrate temperature during film formation is high. Thus, a magnetic alloy thin film suitable as such is obtained.

[Brief description of the drawings]

FIG. 1 shows coercive force and S in a Co—Zr—Sn alloy thin film.
It is an experimental-result figure which shows the relationship with n content.

FIG. 2 shows specific resistance and S in a Co—Zr—Sn alloy thin film.
It is an experimental-result figure which shows the relationship with n content.

FIG. 3 is an experimental result diagram showing a relationship between a coercive force and a substrate temperature in a Co—Zr alloy thin film and a Co—Zr—Sn alloy thin film.

FIG. 4 is an experimental result diagram showing a relationship between a saturation magnetic flux density and a composition in a Co—Zr—Sn alloy thin film.

FIG. 5 shows a Co—Zr—Sn alloy thin film and Co—Zr—S
It is a corrosion-resistive test result figure about an n-Cr alloy thin film.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁷ Identification code FI G11B5 / 31 G11B5 / 31C (56) References JP-A-1-92359 (JP, A) JP-A-55-138049 ( JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01F 10/16 C22C 19/07 C22C 45/04 C23C 14/14 C23C 14/34 G11B 5/31

Claims (3)

(57) [Claims] 1. The method according to claim 1, wherein the content of Co exceeds 92 atomic% and 4.5 to 4.5 atomic%.
An amorphous magnetic alloy thin film containing 6.5 atomic% of Zr and 0.03 atomic% or more of Sn and produced by a vapor phase quenching method. 2. The amorphous magnetic alloy thin film according to claim 1, further comprising 1 to 2 atomic% of Cr in addition to said Co, Zr and Sn. 3. A thin-film magnetic head using the amorphous magnetic alloy thin film according to claim 1 as a magnetic core material.