JPS61179509A - Magnetic material - Google Patents

Abstract

PURPOSE:To improve the magnetic characteristics as well as the working characteristics and to reduce the stress strain between thin film layers, by layering magnetic metal thin films and non-magnetic metal thin films. CONSTITUTION:A substrate 1, formed of a bulky non-magnetic material such as ceramics, glass or metal, carries thereon a soft magnetic material 2a such as permalloy, sendust alloy or amorphous metal provided by a thin film forming means, which may be a dry plating means such as spattering or a wet plating means such as electroplating or electroless plating. Magnetic metal thin film layers 2b and 2c are also provided thereon in a similar manner. Further, a non-magnetic metal material 3a such as aluminum or the like is formed on the magnetic metal thin film layer 2a by a thin film forming means similar to that of the layer 2a. A non-magnetic metal thin film layer 3b is also formed in a similar manner.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic material used, for example, as a core material of a thin-film magnetic head.

[Prior art and its problems]

The magnetic tape used in home video tape recorders currently on the market has magnetic particles made of γ-FezO.
Magnetic tapes of this type have a coercive force of approximately 600 oersteds.

For magnetic tapes with such characteristics, the magnetic head on the recording/reproducing device side has a magnetic material of Mn-Znn.
The mainstream is single-crystal ferrite.

However, with the above-mentioned magnetic tape, it is not possible to obtain the desired image quality and S/N despite improvements accompanying the miniaturization of recording and reproducing devices and higher density recording, and for this reason, the coercive force is low. It is necessary to increase the diameter from about 600 oersted to about 1000 oersted. If such a magnetic tape with a coercive force of about 1000 oersteds is used, sufficient recording cannot be made because the saturation magnetic flux density of the Mn-Zn single crystal ferrite is about 4000 to 5000 Gauss. Furthermore, sufficient reproduction image quality and high S/N ratio cannot be obtained, and high-density recording and reproduction cannot be achieved.

Therefore, in order to solve these drawbacks, we have developed a magnetic material for magnetic heads that has a saturation magnetic flux density approximately twice as high as that of current single-crystal ferrite, and a magnetic permeability that is about the same. It has been considered to use a magnetic material such as a 7-A metal magnetic material or a Sendust alloy magnetic material.

However, if a magnetic head having the same structure as the Jourai magnetic head is constructed using such a metallic magnetic material, the specific resistance is lower than that of the magnetic material of the core due to the metal, and eddy current loss becomes a problem.

Therefore, in order to solve this problem, we used a metal magnetic thin film and 5iOz or At2 as the core material of the magnetic head.
It has been proposed to use a multilayer thin film laminate in which thin films made of oxide-based nonmagnetic materials such as '03 are alternately laminated.

Furthermore, it is possible to make a thin-film type magnetic head using a multilayer thin film laminate in which metal magnetic thin films with a thickness of about 1000 to 100 OA and oxide-based nonmagnetic thin films with a thickness of about 10 to 100 OA are alternately laminated. Proposed.

However, according to the research of the present inventor, such a multilayer thin film laminate of a metal magnetic thin film and an oxide-based nonmagnetic thin film is difficult to form due to the physics of the metal magnetic thin film and oxide-based nonmagnetic thin film that are its constituent materials. For example, the thermal expansion coefficients of metal magnetic thin films and oxide non-magnetic thin films are vastly different.
The stress strain that occurs in a multilayer thin film structure is large, and when processing, for example, by etching, the etching properties are significantly different (metal materials have a faster etching rate than oxide materials), so etching processability is It has become clear that there are some drawbacks.

[Means for solving problems]

A metal magnetic thin film layer and a metal nonmagnetic thin film layer are laminated.

〔Example〕

The drawing is an explanatory diagram of one embodiment of the magnetic material according to the present invention.

In the figure, 1 is a substrate made of a bulk nonmagnetic material such as ceramic, glass, or metal.

2a is made of permalloy, sendust alloy, amorphous metal, etc., formed by a thin film forming means such as dry plating means such as vapor deposition or sputtering, or wet plating means such as electric or electroless plating, on the surface of the substrate 1. It is a metal magnetic thin film layer with a thickness of about 100A to 1 μm made of a soft magnetic material.

Incidentally, 2b and 2c are also metal magnetic thin film layers having the same structure as 2a.

3a is formed by a thin film forming means similar to the above thin film forming means on the surface of the metal magnetic thin film layer 23, such as aluminum, molybdenum, tungsten, titanium, zirconium,
It is a metal nonmagnetic thin film layer with a thickness of about 10 to 1000 A made of a nonmagnetic metal material such as niobium, vanadium, chromium, tantalum, or hafnium.

Incidentally, 3b is also a metal nonmagnetic thin film layer having the same structure as 3a.

Etching processing of a laminated magnetic material configured as described above, for example, a laminated magnetic material in which permalloy is used as the material for the metal magnetic thin film layer, and aluminum or molybdenum is used as the material for the metal nonmagnetic thin film layer. The characteristics are
When a mixed solution of phosphoric acid, nitric acid, hydrochloric acid, and water is used as the etching solution, the metal magnetic thin film layer and the metal nonmagnetic thin film layer are simultaneously etched, resulting in good processing efficiency and processing characteristics.

In addition, since the metal magnetic thin film layer and the metal nonmagnetic thin film layer that make up the laminated magnetic material are both metal materials, there is not much difference in coefficient of thermal expansion. There is no large difference in coefficient of thermal expansion as in the case of using a physical non-magnetic material, so even if these thin film layers are laminated, stress strain is small, and the mechanical properties are excellent.

Furthermore, even if a metal material is used as the non-magnetic thin film material between the metal magnetic thin film layers, the thickness of the metal magnetic thin film layer is approximately 10OA-1μ.
m1 and the thickness of the metal nonmagnetic thin film layer is approximately 10 to 100 OA.
As the total thickness of each layer is increased, the magnetic properties are also significantly improved.

〔effect〕

It has improved magnetic properties, has good etching processing properties, has less stress strain between thin film layers, and has good mechanical properties.

[Brief explanation of drawings]

The drawing is an explanatory diagram of one embodiment of the magnetic material according to the present invention. 2a, 2b, 2c...metal magnetic thin film layer, 3a
, 3b...Metal nonmagnetic thin film layer.

Claims (1)

[Claims] A magnetic material characterized by having a laminated structure of a metal magnetic thin film layer and a metal nonmagnetic thin film layer.