JPS61177630A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve recording characteristics in the magnetic recording direction by impressing a magnetic field in the direction along the circumference of a substrate, and forming a magnetic film of Fe3O4 whose crystal is oriented in the direction along the circumference and an alpha-Fe2O3 thin film, and heat- treating both films to form a gamma-Fe2O3 continuous thin film. CONSTITUTION:Plural fan-shaped magnets 31 are closely arranged in the direction along the circumference of a nonmagnetic discoid substrate 21, and an Fe3O4 substrate thin film 22 is deposited by sputtering on the substrate 21 while impressing a magnetic field in the direction along the circumference. Then an alpha-Fe2O3 thin film 23 is deposited and formed in an Ar-O2 atmosphere on the thin film 22 by reactive sputtering using an Fe target. The crystal in the film 23 is grown and deposited in succession to the crystal orientation of the film 22. Furthermore, the films 22 and 23 are heat-treated in a wet H2 atmosphere to form an Fe3O4 continuous thin film 24. The thin film 24 is heat-treated in the atmosphere to form a continuous magnetic thin film 25 consisting of gamma-Fe2O3 having magnetic anisotropy whose easy magnetization axis is oriented in the direction along the circumference of the substrate 21.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a magnetic recording medium used in a magnetic disk device, and more specifically, the present invention relates to a method for manufacturing a magnetic recording medium used in a magnetic disk device, and more specifically, a method for manufacturing a magnetic thin film in a magnetic recording medium into a disk by a sputtering method. This relates to a manufacturing method that aims to improve the recording density of a magnetic recording medium by easily forming it into a state with magnetic anisotropy so that the recording direction along the circumference of a shaped substrate is the direction of easy magnetization. It is.

In recent years, as the recording density of magnetic recording media has increased, research and development has been actively conducted on magnetic recording media that form continuous magnetic thin films with high saturation magnetization and high coercive force using sputtering methods, which are easy to thin films. The strong, hard (and chemically stable) γ-Fe2O3 thin M odor is attracting attention. Attempts have been made to manufacture a magnetic recording medium having a γ-Fe2O3 continuous magnetic film with magnetic anisotropy in which the recording direction along the circumference of a plate-like substrate is the easy magnetization direction, but it is not easy. Establishment of these manufacturing methods is desired.

[Conventional technology]

Conventionally, as a method for manufacturing a magnetic recording medium having a γ-Fe2O3 continuous magnetic film using a sputtering method,
As shown in FIG. 7, an .alpha.-Fe2O3 thin film 2 is deposited on a non-magnetic disk-shaped substrate 1 made of, for example, alumite-treated aluminum 1) by a reactive sputtering method.

Thereafter, the α-Fe2O3 thin film 2 is heat-treated in a humid IRH2 atmosphere, and as shown in FIG.
By forming a 3O4 thin film 3 and further heat-treating this Fe3O4 thin film 3 in the atmosphere, a magnetic recording medium in which a magnetic thin film 4 made of γ-Fe2O3 is formed as shown in FIG. 9 is obtained. Law or the 10th
As shown in the figure, a thin IQ film made of Fe3O4 is directly deposited on the disc-shaped substrate 1 by sputtering. After depositing the Fe3O4 thin film 3, the Fe3O4 thin film 3 is heat-treated in the atmosphere to form γ-Fe as shown in FIG.
A direct formation method for obtaining a magnetic recording medium having a magnetic layer 1114 made of 2O3 is well known.

[Problem that the invention seeks to solve]

By the way, each of the above-mentioned formation methods can be used, for example, to produce a high-density magnetic recording medium having a γ-Fe2O3 continuous magnetic film with magnetic anisotropy in which the easy magnetization direction is along the circumference of a disk-shaped substrate. In the former indirect formation method, the magnetic properties of the formed magnetic thin film 4 made of γ-Fe2O3 become isotropic, and it is extremely difficult to impart the desired magnetic anisotropy. There were some drawbacks.

In addition, in the latter direct formation method, the base Fe3
Since the range of working conditions related to sputtering when stably and thickly forming the thin film 3 made of O4 is narrow, there is a problem that sputtering control is not easy, and a γ-Fe2O3 continuous magnetic film with good magnetic anisotropy is obtained. The drawback was that it was difficult to do.

[Means for solving problems]

The above problem is solved by applying a magnetic field to a non-magnetic disk-shaped substrate in a direction along the circumference of the substrate, and using a sputtering method to create a magnetic base made of Fe3O4 with crystal orientation in the direction along the circumference. A film is deposited, and α-F,
In the present invention, after an e2O3 thin film is formed by a reactive sputtering method, both of these thin films are heat-treated to form a γ-Fe2O3 continuous magnetic film having magnetic anisotropy that inherits the crystal orientation of the underlying magnetic layer. The problem is solved by a method of manufacturing a magnetic recording medium according to the present invention.

[Effect]

That is, on a non-magnetic disc-shaped substrate, with a magnetic field applied in the direction along the circumference of the substrate, a base magnetic film made of Fe3O4 with crystal orientation in the direction along the circumference is formed by sputtering, By depositing the α-Fe2O3 thin film on the base magnetic layer in advance and using a reactive sputtering method, the α-Fe2O3 thin film is formed in a form that inherits the crystal orientation of the base magnetic layer. Therefore, r -Fe with magnetic anisotropy can be obtained by heat treatment afterwards.
It becomes possible to form a 2O3 continuous magnetic film.

Therefore, a magnetic recording medium suitable for high-density recording can be easily obtained.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIGS. 1 to 4 are enlarged cross-sectional views of essential parts showing step-by-step an embodiment of the method for manufacturing a magnetic recording medium according to the present invention.

First, as shown in FIG. 1, a nonmagnetic disk-shaped substrate 21 made of, for example, alumite-treated aluminum (Aj) is prepared.
A base magnetic layer 22 made of Fe3O4 is formed thereon by sputtering to a thickness less than 2 times the thickness of the total magnetic film.

That is, when forming the base magnetic layer 22, as shown in FIG. The sputtering device is placed in a sputtering apparatus as shown in FIG. 6 with a magnetic field applied thereto.

Next, the board 21 is rotated! 32, sputtering is performed using an Fe target 33 in an Ar-02 atmosphere, thereby depositing and forming a base magnetic film 22 made of Fe3O4 with crystal orientation in the direction along the circumference of the substrate 21. I can do it.

Next, as shown in FIG. 2, Ar-
α-Fe2O3 thin Ill! by reactive sputtering using Fe target in 02 atmosphere. 23 is deposited and formed.

At this time, the α-Fe2O3 thin film 23 is grown and deposited in a manner that follows the crystal orientation of the underlying magnetic film 22 made of Fe3O4.

Therefore, the base magnetic film 22 and α
- After the Fe2O3i4 film 23 is heat-treated (reduced) in a humid H2 atmosphere to form a continuous thin film 24 made of Fe3O4 as shown in FIG. 3, this Fe3O4 continuous thin film 24 is further heat-treated (oxidized) in the atmosphere. By doing so, as shown in FIG. 4, γ-Fe2O3 has magnetic anisotropy with the easy magnetization direction along the circumference of the substrate
It becomes possible to easily form a continuous magnetic thin film 25 consisting of the following.

Note that the method for imparting crystal orientation to the underlying magnetic layer 22 made of Fe3O4 described in this embodiment is not limited to this example;
It is sufficient that the crystal orientation is given in the direction along the circumference of 1.

〔Effect of the invention〕

As is clear from the above explanation, according to the method of manufacturing a magnetic recording medium according to the present invention, the γ-F
Since it is possible to easily form a continuous magnetic thin film made of e2O3 with magnetic anisotropy in which the direction along the circumference is the direction of easy magnetization, the magnetic recording properties in the magnetic recording direction are improved, etc. It has many advantages.

Therefore, a magnetic recording medium suitable for high-density recording and reproduction can be provided.

[Brief explanation of drawings]

1 to 4 are enlarged cross-sectional views of main parts showing an embodiment of the method for manufacturing a magnetic recording medium according to the present invention in the order of steps; FIG. 5 is an arrangement diagram of a magnet for applying a magnetic field to a disc-shaped substrate; FIG. 6 is a schematic configuration diagram of a sputtering apparatus applicable to the manufacturing method of the present invention, and FIGS. 7 to 11 are enlarged sectional views of essential parts for explaining the conventional method of manufacturing a magnetic recording medium. In the figure, 21 is a non-magnetic disc-shaped substrate, 22 is a Fe3O4 base magnetic film, 23 is a cx-Fe2O3 thin film, and 24 is Fe3O
4 continuous thin films, 25 is a γ-Fe2O3 continuous magnetic thin film, 31
3 represents a plurality of fan-shaped magnets, 32 represents a rotating mechanism, and 33 represents an Fe target. III Figure Figure 2 @ 3 Prisoner Figure 4 Figure 5 Figure 6 Number IK7 Figure 8 Figure 9 Figure 10 rM Figure 11

Claims (2)

[Claims] (1) A base magnetic film made of Fe_3O_4 with crystal orientation along the circumference is deposited on a non-magnetic disk-shaped substrate, and an α-Fe_2O_3 thin film is deposited on the base magnetic film by reactive sputtering. After forming, both thin films are heat-treated to form a γ-Fe_2O_3 continuous magnetic film having magnetic anisotropy with easy magnetization direction along the circumference of the substrate. Method. (2) The magnetic base film made of Fe_3O_4 is formed by a sputtering method while applying a magnetic field in a direction along the circumference of the substrate. A method for manufacturing a magnetic recording medium.