JPS6022721A - Thin film magnetic head - Google Patents

Abstract

PURPOSE:To improve the recording/reproducing efficiency of a magnetic head by using a ternary amorphous alloy essentially made of cobalt with addition of a slight amount of hafnium and niobium to form a core thin film of a thin magnetic head. CONSTITUTION:A core thin film 6 is formed on a substrate 1 via a core thin film 2, an insulated thin film 3, a conductive thin film 4 and an insulated thin film 5 respectively. The films 2 and 6 are made of a ternary amorphous alloy of Co-Hf-Nb with the contents of 91.1, 2.2 and 6.7atom% respectively. These three components are obtained through a heat treatment in a rotary magnetic field at 300-400 deg.C, at 10-20rpm, with >=100Oe intensity of magnetic field and in >=3hr respectively. As a result, the anisotropic magnetic field can be reduced.

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.
The core thin 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 increase recording efficiency, the first and second core thin films are coated with
It is necessary to use soft magnetic materials with high magnetic permeability and high saturation magnetic flux density.

Conventionally, permalloy or the like has been used as the first and second core thin films 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 the signal will not be processed, especially for magnetic recording media with high saturation magnetic flux density such as metal tape or chrome tape. When recording, the recording efficiency is poor.

Therefore, it is possible to suppress the decrease in recording efficiency by increasing the number of turns of the coil or increasing the recording current. However, increasing the number of turns in the coil is difficult due to the structure of the thin film magnetic head, and is limited to 3 to 5 turns.
Not enough 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 present inventors found that the main component is cobalt (G o ) and a small amount of hafnium (Hf).
) and niobium (Nb) are added to a ternary amorphous alloy of Go-Hf-Nb, which is very suitable as the core thin film of a thin-film magnetic head.

Using crystallized glass as the substrate, a cobalt disk (diameter 1
Hafnium pellets and niobium pellets (both pellets are vertically
The pellets are arranged alternately radially from the center, and the alloy composition can be changed by adjusting the number of pellets on the target. Then, the degree of vacuum was set to a high vacuum of less than I
By performing sputtering at 0 m'', it is possible to create a three-component Go-Hf-Nb amorphous alloy thin film with cobalt as the main component on the substrate. Alloy samples of various compositions created in this way is used for each characteristic test described below.

FIG. 1 is a magnetic characteristic diagram when the Hf content X is varied while the Nb content Y in the alloy is always 6.7 atomic % in the alloy composition table described later.

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 500 KHz; the curve He is the coercive force in the hard axis direction.

As is clear from this figure, C with an Hf content of 0 atomic %
The o -N b binary alloy has high Bs, but too high He and low He. When a small amount of Hf is added to this, He
decreases extremely, while He increases. Note that when the content of Hf exceeds a certain level, He becomes high and 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 increase μe while maintaining Bs high, the Hf content X
It is necessary to limit 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 Nb content Y is slightly changed.

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

As is clear from this figure, C with a Nb content of 0 at%
As mentioned above, the o-Hf binary alloy also has high Bs, but
Hc is too high and He is low. By adding a small amount of Nb to this, the He content decreases extremely, and on the contrary, the He content increases.

Note that when the Nb content exceeds a certain level, -He becomes high and He becomes low. On the other hand, Bs tends to decrease as the Nb content increases, although this is not extreme.

Given these characteristic trends, in order to lower He and increase μe while maintaining Bs high, the Nb content Y
It is necessary to control the content within the range of 4 to 8 atom %, preferably 4 to 6 atom %. This holds true even if the Hf content X is slightly changed.

The three-component amorphous alloy of Go - Hf - N b according to the present invention tends to exhibit induced magnetic anisotropy (X). By the way, in the case of a ternary alloy of G o -Hf -Nb, the anisotropic magnetic field Hk of the thin film immediately after sputtering is large.As a result of various studies on means to reduce this anisotropic magnetic field, we found that the core We have found that it is effective to heat-treat the three-component amorphous alloy thin film formed as a thin film in a rotating magnetic field.
~400 (℃), rotation speed is 10~2Q (r, p, m
), magnetic field strength is 100 (Oe) or more, processing time is 3
More than an hour is appropriate. For example, if the temperature is 350 ("C),
Rotation speed: 10 (r, p, m,) Magnetic field strength: 100
(Oe), by setting the processing time to 3 hours and treating the core thin film formed by sputtering, the anisotropic magnetic field Hk can be lowered to about 4 (Oe).

FIG. 3 is a partially sectional perspective view of a thin film magnetic recording head according to an embodiment of the present invention. On a substrate 1 made of a non-magnetic material such as glass or silicon, a thin core yA2 with a first node 1 is formed, and an insulating # film 3 made of a non-magnetic material is formed thereon. The second core thin film 6 is passed through the electrocardiogram thin film 4 and the insulating thin film 5.
is formed.

These first core thin films [2, insulating thin films 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
It is made of a three-component amorphous alloy thin film of -Hf-Nb and has a Go content of 91.1 at%.

The Hf content is 2.2 atomic %, the Nb content is 6.7 atomic %, and heat treatment is performed 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 niobium 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 the drawing]

FIG. 1 is a characteristic diagram showing the relationship between the Hf content and various magnetic properties in the Go-Hf-Nb-based amorphous alloy according to the present invention, and FIG. 2 is a characteristic diagram showing the relationship between the Nb content in the alloy and various magnetic properties. FIG. 3 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... First core thin film, 3... Insulating thin film, 4... Conductive thin film, 5... M edge thin film, 6...
Second core thin film. Figure 2 Nb content (at%) Figure 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 a nonmagnetic material, the core thin film However, 3 contains cobalt as the main component and small amounts of hafnium and niobium are added.
A thin film magnetic head characterized by being composed of an amorphous alloy. (2. Claims@(1), wherein the hafnium content is IM % or more and less than 5 atomic %,
A thin film magnetic head characterized in that the content of niobium is regulated to be 4 atomic % or more and 8 atomic % or less. (3) A thin film magnetic head according to claim (1), characterized in that the thin film of a ternary amorphous alloy of cobalt-hafnium-niobium formed as the core thin film is heat-treated in a rotating magnetic field. .