JPH05282647A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve the high-frequency characteristics of a magnetic recording medium by forming a recording layer on a backing layer of a soft magnetic oxide. CONSTITUTION:A backing layer 10' of a soft magnetic oxide is formed on a Cr underlayer 22 on a glass substrate 20, a recording layer 14' of Co-Cr is formed on the backing layer 10' and a protective layer 16 and a lubricative layer 18 are further superposed on the recording layer 14'. The soft magnetic oxide may be bulky ferrite. When a magnetic field for recording is applied through the resulting magnetic recording medium with a perpendicular magnetic head, eddy current loss in a high-frequency region is not caused because the soft magnetic oxide having high electric conductivity exists under the recording layer 14'. As a result, excellent high-frequency characteristics are ensured for the recording medium.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to recording and reproducing magnetic information such as a rigid magnetic disk used in a fixed magnetic disk device, a flexible magnetic recording medium used in a flexible disk device and a magnetic tape device. The present invention relates to a magnetic recording medium.

[0002]

2. Description of the Related Art In perpendicular magnetic recording, recording / reproducing is generally performed on a recording medium having magnetic anisotropy perpendicular to the film surface by using a magnetic head capable of applying a magnetic field in the perpendicular direction. In particular, as a magnetic head, a perpendicular magnetic head as shown in FIG. 1 is suitable, and as a recording medium combined therewith, a recording medium having a two-layer structure of a recording layer and a soft magnetic backing layer shown in FIG. 2 is an optimal device. It is known.

[0003]

It has been found that this perpendicular magnetic head applies a recording magnetic field through the recording medium due to its operating principle, so that the high frequency characteristics are deteriorated due to eddy current loss in the high frequency region. This is shown in FIG. 3 which shows the frequency dependence of ΔL / Lo in the single layer film and the laminated film of the soft magnetic backing layer of Fe-Ni-Nb.

This phenomenon is due to the fact that the soft magnetic film forming the backing layer is a metal material such as permalloy and has a low conductivity, so that a large eddy current is generated. Furthermore, since the eddy current is generated in the in-plane direction of the magnetic film due to the basic structure of the recording medium, it is theoretically difficult to solve it by devising the structure. Therefore, the only solution is to increase the conductivity by changing the material of the backing layer. This backing layer is required to be soft magnetic from the operating principle, but the soft magnetic material can be roughly classified into a metal material and an oxide material, and at the same time, the conductivity of these two types of groups is significantly different. Are known.

An object of the present invention is to provide a novel magnetic recording medium having excellent high frequency characteristics by increasing the conductivity of the backing layer.

[0006]

The above objects of the present invention are as follows.
This is achieved by providing a magnetic recording medium in which the soft magnetic layer is composed of a soft magnetic oxide.

More specifically, in a so-called perpendicular magnetic recording system in which recording magnetization is formed perpendicularly to a plate surface in the recording medium, the recording medium is a substrate composed of a recording layer for accumulating recording magnetization and a soft magnetic oxide. Provided is a magnetic recording medium having as a main component.

Further, in a so-called perpendicular magnetic recording system in which recording magnetization is formed in a recording medium perpendicularly to the plate surface,
(EN) Provided is a magnetic recording medium, which comprises a recording layer for accumulating recording magnetization, a backing layer made of a soft magnetic oxide and a non-magnetic substrate disposed thereunder as main components.

[0009]

In this structure, the recording magnetic field is applied through the recording medium by using the perpendicular magnetic head. However, since the soft magnetic oxide having high conductivity is formed under the recording layer, There is no eddy current loss in the high frequency region, and therefore the magnetic recording medium has excellent high frequency characteristics.

[0010]

EXAMPLE 1 Example 1 is a recording medium which is required to have flexibility. As shown in FIG. 6, a soft magnetic oxide 10 is formed on a plastic film 12 by, for example, a sputtering method.
The recording layer 14 is formed on the above, and the recording layer 14 made of a Co—Cr layer is further provided thereon. Reference numerals 16 and 18 are a protective layer and a lubricating layer, respectively.

The second embodiment is applied to a rigid recording medium such as a fixed magnetic disk, and 10 'is made of a soft magnetic oxide formed on the Cr underlayer 22 of the glass substrate 20. It is a backing layer on which Co-Cr
A recording layer 14 'composed of layers is provided, and a protective layer 16 and a lubricating layer 18 are provided as usual. The soft magnetic oxide is made of bulk ferrite, for example.

[0012]

FIG. 4 shows the results of comparing the frequency characteristics of the soft magnetic oxide and the backing layer of the soft magnetic metal film as the head inductance. Also, the actual head
The results of measuring the recording / reproducing characteristics of the recording medium are shown in FIG. All of them show that the frequency characteristics are improved.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a magnetic head.

FIG. 2 is an enlarged cross-sectional view of a magnetic recording medium made of a conventional rigid magnetic disk medium.

3 is a graph showing frequency characteristics of the magnetic recording medium shown in FIG.

FIG. 4 is a grab showing a result of comparison of frequency characteristics as head inductance using a backing layer of a soft magnetic oxide film and a soft magnetic metal film.

FIG. 5 is a grab showing a result of measuring recording / reproducing characteristics.

FIG. 6 is an enlarged sectional view of an embodiment of a magnetic recording medium according to the present invention.

FIG. 7 is an enlarged cross-sectional view of another embodiment of the magnetic recording medium according to the present invention.

[Explanation of symbols]

 10, 10 'Soft magnetic oxide 14, 14' Recording layer 12 Plastic film 16 Protective layer 18 Lubricating layer 20 Glass substrate 22 Underlayer

Claims (2)

[Claims] 1. In a so-called perpendicular magnetic recording system in which recording magnetization is formed perpendicularly to a plate surface in the recording medium, the recording medium mainly comprises a substrate composed of a recording layer for accumulating recording magnetization and a soft magnetic oxide. A magnetic recording medium as a component. 2. In a so-called perpendicular magnetic recording system in which recording magnetization is formed perpendicularly to a plate surface in the recording medium, the recording medium has a recording layer for accumulating the recording magnetization and a backing layer made of a soft magnetic oxide. A magnetic recording medium whose main component is a magnetic substrate.