JPH01283908A - Co based amorphous magnetic film and magnetic head using the film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a magnetic film used for a magnetic head pole suitable for high-density magnetic recording, and in particular has a high saturation magnetic flux density, a high crystallization temperature, and a low magnetostriction. The present invention relates to a Go-based amorphous magnetic film and a magnetic bed using the same.

[Conventional technology]

There has been remarkable progress in increasing the density and performance of magnetic recording. In the field of magnetic disk drives for large computers, large capacity improvements have been made due to significant improvements in recording density. In magnetic disk drives, it is essential to use thin-film heads that have lower inductance and higher high-frequency magnetic permeability than conventional ferrite bulk heads, and can be processed into narrow track widths.

In thin-film heads, magnetic poles must be made thinner in order to improve resolution as recording density increases, and magnetic saturation is likely to occur at the tips of thin magnetic poles.

Therefore, a thin film head using a magnetic film with a high saturation magnetic flux density is required.

Conventionally, magnetic films for thin film heads have mainly been made of N i −
Fa-based alloy film (permalloy film) has been used*
Although the N iFe alloy has excellent corrosion resistance, its saturation magnetic flux density is 1.0T. N1-Fa is no longer able to cope with future increases in saturation magnetic flux density.

In recent years, amorphous sputtered films have been developed as high-performance magnetic films with high saturation magnetic flux density. Among these, especially M a
Zr-based amorphous alloys represented by the composition formula T a Z r have superior heat resistance compared to amorphous alloys whose vitrification elements are metalloid elements such as B, Si, and P. ,
It has excellent properties as a magnetic film for magnetic heads.

Here, M in the above compositional formula is Go having a magnetic moment,
T is at least one of Fe and Ni, and T is a transition metal other than M and Zr. Regarding such amorphous alloys in which the vitrifying element is mainly Zr, Japanese Patent Application Laid-Open No. 1986-
138049 and JP-A-56-84439. Among these Zr-based amorphous alloys, M is c
The Co-Zr alloy consisting of o has a high saturation magnetic flux density and is an excellent magnetic material.

However, the magnetostriction constant of this amorphous alloy is 2~4xio-
V, Nb, and Ta, which make a negative contribution to the magnetostriction constant of the amorphous alloy, are added as additive elements T because they exhibit a relatively large value as e.
By using elements such as 9Mo, W, and R, an amorphous alloy with a magnetostriction constant of approximately 0 can be obtained. Among these, IEEE TRANSACTIONS on Magnetics, 1985, Volume 21° Number 5 (IEEE TRANSACTIONS
ON MAGNE Ding IC31985Vo Q, MAG
-21,N(15), pages 2032 to 2034, the CoReZr amorphous film has excellent corrosion resistance and has a saturation magnetic flux density of 1.3 in a magnetostrictive field.
It is considered to be promising as a thin film magnetic head because of its high T.

[Problem to be solved by the invention]

However, the CoReZr amorphous film has poor heat resistance, and when compared at the same saturation magnetic flux density, the C of the magnetostrictive field
o T a Z r The crystallization temperature is about 50° C. lower than that of the amorphous magnetic film, and there is a problem that crystallization occurs during the high temperature process when manufacturing the magnetic head.

[Means to solve the problem]

In the present invention, instead of Zr as an amorphous element of Co,
By using CoReHf using Hf, the crystallization temperature can be raised by approximately 60°C without deteriorating the corrosion resistance, making it a good magnetic head material that does not crystallize even during high-temperature treatment in the magnetic head manufacturing process. This is what I got.

〔Example〕

FIG. 1 shows a characteristic diagram of a CoReHf alloy sputtered film. CoReHf was formed using a two-pole high frequency sputtering device. Distance between poles is 50m, Ar pressure is 5 x 10-3
Torr, and the input power was 175W. The substrate was water cooled. FIG. 2 shows a characteristic diagram of the CoReZr alloy sputtered film. The composition dependence of the magnetostriction and saturation magnetic flux density of the CoReHf alloy sputtered film is almost the same as that of CoReZr. The magnetic pole material of a thin film magnetic head needs to have a high saturation magnetic flux density and a low magnetostriction. Therefore, as for the composition of CoReHf, the Co composition is 90 at% or more and less than 95 at%, the Re composition is Q, 5 at% or more and less than 5 at%, and the Hf composition is 3a
It is appropriate that t% or more and 9.5 at% not dropped.

FIG. 3 shows CoTaZry CoReZr and C
It shows the relationship between the saturation magnetic flux density and the crystallization temperature when the magnetostriction of the o Re Hf-based alloy sputtered film is set to O.

When compared at the same saturation magnetic flux density, Co Re Hf
The crystallization temperature of the CoReZr-based alloy sputtered film is about 60°C higher than that of the CoReZr-based alloy sputtered film, and it has heat resistance that is equal to or higher than that of the CoTaZr-based amorphous film. Understood.

FIG. 4 shows CoTaZr and CoReZr.

The relationship between the saturation magnetic flux density and corrosion resistance when the magnetostriction of a CoReHf amorphous alloy sputtered film is made zero is shown.

Corrosion resistance is shown by the amount of change in saturation magnetization after performing a salt spray test and leaving it for 100 hours.

In other words, the amount of corrosion is (M s (0) M s (1
00))/Ms(0)X100(%). Here, M s (t) is the saturation magnetization after time. For any alloy type, the larger the saturation magnetic flux density, the
That is, the larger the Go composition, the larger the amount of corrosion, and the worse the corrosion resistance. However, if we compare the same saturation magnetic flux density, CoRaHf, CoTaZr
.

It was found that the corrosion resistance was excellent in the order of CoReZr.

Example 2 A thin film magnetic head was formed using Co　Re　Hf.

The CoReHf amorphous alloy was formed using a high frequency two-pole sputtering device. The ultimate vacuum level is 8 x 10'''7 torr,
Ar gas pressure was 5 x 10''-'torr. Power input during sputtering was 175 W, and the substrate was water-cooled. The film formation rate at this time was 100 A/min. Immediately after film formation, one surface was It has uniaxial anisotropy inside,
The anisotropic magnetic field was about 200e.

In order to improve the soft magnetic properties, that is, to reduce the anisotropic magnetic field, heat treatment in a magnetic field or heat treatment in a rotating magnetic field was performed. FIG. 5 shows Co s x Re 2 Hf e
(at%) amorphous alloy at 1kO in the direction of the easy magnetization axis of the film.
After heat treatment at 400°C for 1 hour by applying a DC magnetic field of 380°C, a DC magnetic field of IKOe was applied in the axial direction
This figure shows the dependence of the anisotropic magnetic field Hk on the heat treatment time when the heat treatment was performed at .degree. C. for minutes.

Figure 6 shows a CoezRezHfe (at%) amorphous alloy under magnetic field magnitude I K Oe and rotation speed 50 Orpm.
, which shows the dependence of the anisotropic magnetic field Hk on the heat treatment time when heat treatment was performed at a heat treatment temperature of 400° C. for minutes.

In any of the above cases, the anisotropic magnetic field can be changed by heat treatment. However, the value of Hk that could be controlled with good reproducibility was 5 K Oe. Furthermore, similar results were obtained even when the composition and thickness of the magnetic film were changed.

FIG. 7 shows a cross-sectional view of the main parts of a thin-film magnetic head manufactured using a CoReHf amorphous film as a magnetic pole.

The thin film magnetic head includes a lower magnetic layer 2 of the Co ez Re z Hf e amorphous film formed on a nonmagnetic substrate 1 of AQz○δ-TiC, a gap layer 3 of AQzOδ, and a C
u.

Conductor coil such as AQ 4. It consists of an organic insulating layer 5 made of a polyimide resin such as PIQ (a trademark of polyimide resin manufactured by Hitachi Chemical Co., Ltd.), and an upper magnetic layer 6 of the CoI+zRetHfe amorphous film. For film formation of the thin film head, techniques known in the semiconductor manufacturing process were used.

By the way, when PIQ is used for the organic insulating layer, heat treatment is required to harden the PIQ.

It is said that the heat treatment temperature requires a maximum of 350° C., and the heat treatment time requires a minimum of 10 hours.

Figure 8 shows Go9zTaaZra and Co5zRazZr.
It shows the dependence of coercive force on heat treatment time when an e+Co5zRe2Hfe amorphous film is heat treated at 350°C.

CoezTaaZra, Co5zRezHfs is 35
There was no change in coercive force even after heat treatment at 0°C for 20 hours.

The coercive force of CoexRezZre begins to increase after about 5 hours. According to X-ray diffraction analysis, the increase in coercive force likely corresponds to the crystallization of CoezRezZre. Therefore, CoexRexZr
CoszTagZrδ crystallizes during the manufacturing process of the thin film magnetic head.

It was found that CoezReIIHfe does not crystallize and maintains its soft magnetic properties even during the thin film head manufacturing process.

The thickness of the magnetic film was 1.5 μm for the upper magnetic layer, 1.1 μm for the lower magnetic layer, and 12 μm for the track width.

The flying height of the prototype head was 0.3 μm, the head medium relative speed was 40 m/s, and the y-FezOa medium (coercive force 450
0s) to investigate the recording and reproducing characteristics. The playback output is
300 μV p-p was obtained.

〔Effect of the invention〕

According to the present invention, a co-based amorphous film having a high saturation magnetic flux density, a high crystallization temperature, and a low magnetostriction can be obtained, and a head using this film exhibits excellent recording and reproducing characteristics.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the magnetic properties of a CoReHf alloy sputtered film, FIG. 2 is a diagram showing the magnetic properties of a CoRaZr alloy sputtered film, and FIG. 3 is a diagram showing the magnetic properties of a CoTa Zr alloy sputtered film. Figure 4 shows the relationship between the saturation magnetic flux density and the crystallization temperature when the magnetostriction of the CoReZr, CoReHf based alloy sputtered film is set to O.
r. Figure 5 shows the relationship between saturation magnetic flux density and corrosion resistance when the magnetostriction of a CoReZr, CoReHf based alloy sputtered film is set to O. Figure 6 is a diagram showing the relationship between the anisotropic magnetic fence and the heat treatment time.
A diagram showing the relationship between the anisotropic magnetic field and the heat treatment time when an Hfe amorphous alloy is heat treated in a rotating magnetic field. Figure 7 is a schematic cross-sectional view of the main image of the prototype thin-film magnetic head. Figure 8 is a diagram showing the relationship between the anisotropic magnetic field and the heat treatment time. ,Co
ezT a eZrs. FIG. 3 is a diagram showing the heat treatment time dependence of coercive force of CoezRazHfs and Co5zRezZrs amorphous films.

Claims (1)

[Claims] 1. A Co-based amorphous magnetic film characterized by having a component composition represented by the following formula (1). Co_ARe_BHf_C...(1) However, the following conditions are satisfied: 90≦A≦95, 0.5≦B≦5, 3≦C≦9.5, and A+B+C=100. (However, the unit is at%)2. A magnetic head using the magnetic film according to claim 1.