JPS6022723A - Thin film magnetic head - Google Patents

Abstract

PURPOSE:To improve the recording and reproducing efficiency of a magnetic head by constituting thin core films of a ternary amorphous alloy which consists essentially of cobalt and is added with a small amt. of hafnium and tungsten. CONSTITUTION:A thin core film 2, a thin insulating film 3 consisting of a nonmagnetic material, a thin conductive film 4 and a thin core film 6 via a thin insulating film 5 are formed on a base plate 1. The films 2 and 6 consist of a thin film of a ternary amorphous alloy consisting of Co-Hf-W and are obtd. by regulating the respective contents in the alloy to 90.8atom% Co, 2.2atom% Hf and 7.0atom% W and heat-treating the alloy in a rotating magnetic field. The treating conditions thereof are 300-400 deg.C temp., 10-20rpm rotating speed and >=100Oe intensity of the magnetic field and >=3hr treating time. The anisotropic magnetic field is decreased to about 4Oe by such treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thin film magnetic head, and particularly to the material of the core thin film thereof.

A thin film magnetic recording head has a first magnetic recording head on a substrate made of a non-magnetic material.
A core film, a nonmagnetic material thin film, and a second core thin film are formed in a laminated state by sputtering, vapor deposition, or the like.

This thin film magnetic recording head is paired with a thin film magnetic reproducing head to form a thin film magnetic head, which is used, for example, in a storage device of an electronic computer. In a thin film magnetic recording head, in order to improve recording efficiency, it is necessary to use a soft magnetic material having high magnetic permeability and high saturation magnetic flux density for the first and second core thin films.

Conventionally, permalloy or the like has been used for the first and second cores of this type of magnetic head, but this material has a low saturation magnetic flux density. If the saturation magnetic flux density is low, the core thin film will be magnetically saturated during recording, and recording efficiency will be poor, especially when recording C signals on magnetic recording media with high saturation magnetic flux density, such as metal tape or chrome tape. .

It is highly recommended to suppress the decrease in recording efficiency by increasing the turn JII of the coils and the recording current or by increasing the recording current. However, increasing the number of turns in the winding coil is difficult due to the structure of the thin-film magnetic head, and is limited to about 3 to 5 turns, making it impossible to obtain a sufficient effect. On the other hand, when the recording current is increased, the amount of heat generated increases, causing wire breakage and magnetic deterioration of the core thin film.

As a result of various studies on amorphous alloy thin films obtained by sputtering etc., the inventors of the present invention have found that the main component is Kobal i'' (Go), and hafnium (Hf) in the evening scene.
and tungsten (W) added f = CO-Hf-W 3
Thin films made of amorphous alloys are used for thin film magnetism.
It has been found that it is very suitable as a core thin film for RAD.

Using crystallized glass as the substrate, a cobalt disk (diameter 1
Hafnium pellets and tungsten pellets (10mm long, 10mm wide, 1mm thick) are placed alternately radially from the center on the target. The alloy composition can be changed by adjusting the number of -. Then, the degree of vacuum is set to a high vacuum of less than l Amorphous alloy thin films of various types can be created.Alloy samples of various compositions created in this way are used for each characteristic test described below.

Figure 1 shows the Hf content
It is a magnetic characteristic diagram when changing variously.

In the alloy composition table, the curve Bs is the saturation magnetic flux density; the curve μe is the magnetic permeability in the hard axis direction at a frequency of I MHz; and the curve He is the coercive force in the hard axis direction. As is clear from this figure, the Co-W22 alloy with an Hf content of 0 atomic % has high Bs, but too high Hc and low He. When a small amount of Hf is added to this, Hc drops extremely, while He increases.

Note that when the content of Hf exceeds a certain level, He becomes low. On the other hand, Bs tends to decrease as the Hf content increases, although it is not extreme.

Given these characteristic trends, in order to lower He and achieve high μB while keeping Bs high, the Hf content X
It is necessary to control the content to a range of 1 atomic % or more and less than 5 atomic %, preferably 1.5 to 3 atomic %. This holds true even if the W content Y is slightly changed.

Figure 2 shows that in the alloy composition table, the Hf content X in the alloy is always 2.2yK%, and the W content Y
It is a magnetic characteristic diagram when changing variously.

As is clear from this figure, C with a W content of OyK%
As mentioned above, the o-Hf binary alloy also has a high BS, but
He is too high and He is low. By adding a small amount of W to this, He becomes extremely low, and conversely becomes high. Note that when the W content exceeds a certain level, He becomes low. On the other hand, Bs tends to decrease as the W content increases, although this is not extreme.

Given these characteristic trends, in order to lower He and increase μe while maintaining high Bs, the W content Y should be in the range of 5 to 12 atomic %, preferably 6 to 8 atomic %. It needs to be regulated. This holds true even if the Hf content X is slightly changed.

Since the Go-Hf-W three-component amorphous alloy according to the present invention tends to exhibit induced magnetic anisotropy, it is possible to orient the difficult axis of magnetization of the amorphous alloy in the direction of operation of the core thin film in consideration of high frequency characteristics. can. By the way, G o -H
In the f-W ternary alloy, the anisotropic magnetic field Hk of the thin film immediately after sputtering is large. As a result of various studies regarding means for reducing this anisotropic magnetic field, it was found that a method of heat-treating the ternary amorphous alloy thin film formed as the core thin film in a rotating magnetic field is effective.

In this heat treatment in a rotating magnetic field, the temperature is 300 to 400 (℃
), a rotational speed of 10 to 20 (r, p, m,), a magnetic field strength of 100 (Oe) or more, and a processing time of 3 hours or more. For example, the temperature is 350 (℃), the rotation speed is 10 (r-p, m,), the magnetic field strength is 100 (Oe),
If the processing time is set to 3 hours and the core thin film formed by sputtering is processed, the anisotropic magnetic field Hk will be approximately 4 hours.
(Os).

FIG. 3 is a partially sectional perspective view of a thin film magnetic recording head according to an embodiment of the present invention. A first core thin film 2 is first formed on a substrate 1 made of a non-magnetic material such as glass or silicon, and an insulating thin film 3 made of a non-magnetic material is formed thereon. A second core thin film 6 is formed via the conductive thin film 4 and the insulating thin film 5.

These first core thin @2. Insulating thin film 3. The conductive thin film 4, the insulating thin film 5, and the second core thin film 6 are sequentially formed to a predetermined thickness by a film forming technique such as sputtering.

Note that 4a and 4b are terminal portions for external connection.

The first core thin film 2 and the second core thin film 6 are Go
- Consisting of a three-component amorphous alloy thin film of Hf-W
The content of O is 90.8 atomic %, the content of Hf is 2.2 atomic %, and the content of W is 7.0 atomic %, and is heat-treated in a rotating magnetic field under the above-mentioned conditions.

As described above, the present invention is characterized in that the core thin film of the thin film magnetic head is composed of a three-component amorphous alloy containing cobalt as a main component and to which small amounts of hafnium and tungsten are added.

Since this three-component amorphous alloy has high saturation magnetic flux density and magnetic permeability, it is possible to improve the recording efficiency and reproduction efficiency of the magnetic head.

[Brief explanation of drawings]

FIG. 1 is a characteristic diagram showing the relationship between the Hf content and various magnetic properties in the Go-Hf-W amorphous alloy according to the present invention, and FIG. 2 is a characteristic diagram showing the relationship between the W content in the alloy and various magnetic properties. FIG. 3 is a characteristic diagram showing the relationship, and is a partially sectional perspective view of a thin film magnetic head according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Substrate, 2... 1st core thin film, 3... Insulating thin film, 4... Conductive thin film, 5... Insulating thin film, 6... 2nd core reflection. Fig. 2 W including morning ya (Gt%) Fig. 3

Claims (1)

Scope of Claims: (1) In a thin film magnetic head in which a first core thin film, a nonmagnetic material thin film, and a second core thin film are formed in a laminated state on a substrate made of nonmagnetic H, the core thin film A thin film magnetic head characterized in that it is made of 4J of a three-component amorphous alloy containing cobalt as a main component and adding small amounts of hafnium and tungsten. (2. In claim (1), the hafnium content is 1 atomic % or more and less than 5 atomic %, 1
1θ, tungsten content is 5 at% or more and 12
A thin film magnetic head characterized by being regulated to atomic percent or less. (3) In claim (1), the thin film magnetic thin film is characterized in that the core thin film formed as the cobalt-hafnium-tungsten ternary amorphous alloy thin film is heat-treated in a rotating magnetic field. head.