JPH0773435A - Magnetic recording medium and its production - Google Patents

Abstract

PURPOSE:To provide a magnetic recording medium having magnetic characteristics suitable for high-density recording by forming a ground surface film, magnetic film, etc., by a sputtering method right on the morphous films which consist of an Si film and C film formed by a sputtering method, etc., on a nonmagnetic substrate and are made amorphous. CONSTITUTION:This magnetic recording medium is constituted by forming the ground surface film consisting essentially of Cr, magnetic film, protective film and lubricative film on the nonmagnetic substrate consisting of glass, etc. The C film which is made amorphous by the Si film formed on the nonmagnetic substrate side is interposed between the nonmagnetic substrate and the ground surface film. As a result, the magnetic recording medium having the magnetic characteristics suitable for high-density recording is obtd. The films made amorphous by the Si film and the C film improve the adhesion property to the nonmagnetic substrate and prevent the diffusion of the gases or ions from the nonmagnetic substrate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium in which various films are sequentially laminated on a non-magnetic substrate to form an integrated magnetic recording medium. It is about.

[0002]

2. Description of the Related Art In a conventional magnetic recording medium, a base film, a magnetic film, a protective film and the like are sequentially formed on an Al substrate plated with Ni-P by a sputtering method or the like, and then a lubricant is coated on the surface. It is made by.

Among the above various films, the magnetic film is
For example, JP-A-61-292219 and JP-A-62-1922
239420, or Japanese Patent Laid-Open No. 62-137720.
As disclosed in Japanese Patent Publication No.
It has been proposed to form a three-element or four-element alloy containing b, Ta, Cr, Ni, etc. by a sputtering method or the like. Further, as the base film, for example, Japanese Patent Laid-Open No. 62-
Cr or Cr alloys are used as shown in JP-A-257618, JP-A-63-106917, or JP-A-61-292219.

Furthermore, recently, as a non-magnetic substrate,
In order to increase the recording density, it is considered to change the material from a conventional Al substrate to a glass or carbon substrate which is light and strong and has excellent flatness.

[0005]

However, even if the glass or carbon substrate is used as it is instead of the conventional Al substrate as the non-magnetic substrate, some of the elements present on the surface of the glass or carbon substrate are used. Is Cr
Alternatively, H ₂ O and H _{2 which} are diffused into a base film made of a Cr alloy or retained (included) in pores or grain boundaries existing in a glass or carbon-based substrate are released. Due to the diffusion of ions, for example, the coercive force (Hc) in the magnetic film is lowered and the hysteresis of the magnetization represented by the squareness ratio becomes unsuitable, so that high recording density may not be achieved.

[0006]

DISCLOSURE OF THE INVENTION The inventors of the present invention have conducted extensive studies to solve the above problems and achieve a higher recording density. As a result, a non-magnetic substrate, a base film, a magnetic film, a protective film and a lubrication film have been obtained. A magnetic recording medium having a film as a basic structure, wherein S formed between a non-magnetic substrate and a base film is formed on the non-magnetic substrate side.
The present inventors have found a magnetic recording medium characterized by interposing a C film amorphized by an i film (hereinafter referred to as an amorphized film) and a manufacturing method thereof.

Generally, in order for the magnetic film to exhibit its performance, the properties of the underlying film located immediately below it are related, and the properties of this underlying film are affected by the surface of the intervening film located immediately below. As a result, the conditions that the intervening film should have are as follows. The surface should be amorphous. Gas or constituent elements should not diffuse into the underlying film from the inside of the intervening film. The non-magnetic substrate and the intervening film, and the intervening film and the underlying film have sufficient adhesion and blocking properties, respectively.

In Japanese Patent Laid-Open No. 4-247323, a Ti film and a Si film are sequentially coated and laminated on the surface of a non-magnetic support, and then heat treatment is performed to convert the Si into the Ti film.
A magnetic recording medium having a thermally diffused amorphous alloy layer formed therein is described, and it is disclosed that the magnetic recording medium can improve magnetic characteristics. However, in the above magnetic recording medium, since the substrate side is Ti and the underlayer side is Si inside the intervening film, excess Si may be present in the upper portion inside the intervening film, and this excess Si component is present. Since it partially reacts with Cr in the base film laminated directly on the film, it is not possible to create stable conditions for the base film.

Each component of the magnetic recording medium of the present invention will be described. The non-magnetic substrate, undercoating film, magnetic film, protective film and lubricating film are not particularly limited in their materials and compositions, but may be known ones. It can be appropriately selected and used, and the film forming method is not particularly limited. For example, as the non-magnetic substrate, a glass-based substrate such as canasite glass or tempered glass or a carbon-based substrate can be used. Further, as described above, a base film made of Cr or a Cr alloy may be used, and a magnetic film containing Co as a main component may be formed by a sputtering method.

Further, the amorphized film is a Si film and a C film.
It is obtained by sequentially forming a film and a film and then heating if necessary. The amorphization rate of the Si film and the C film varies depending on the heating temperature and the silicide composition, but the sputtering temperature (300 to 50) in the actual operation.
At 0 ° C., it is approximately 100 to 200 Å / min. When Si reaches the uppermost portion of the C film by diffusion, the entire C film is amorphized.
The thickness (upper limit) of the C film is set to such a degree that the diffusion of Si can reach the uppermost portion of the C film in the heating temperature in the actual operating state and the time until the underlying film immediately above is sputtered. Is preferred. Normally, its thickness is 1
It is 0 to 200Å. On the other hand, the thickness of the Si film is 20 to 15
It is set to 00Å, preferably 30 to 1000Å. S
When the thickness of the i film is 20 Å or less, the adhesion is insufficient, and the function as a getter for O ions and the like that diffuse and diffuse from the non-magnetic substrate becomes insufficient. Further, if the thickness is 1500 Å or more, the practical meaning becomes small and the productivity is lowered.

To manufacture the magnetic recording medium of the present invention, a Si film and a C film are formed on a non-magnetic substrate by a sputtering method or other means to make them amorphous, and an amorphous film is used as an intervening film. After the formation of the oxide film, the underlying film, the magnetic film, the protective film and the lubricating film are formed directly on the oxide film by the sputtering method or other conventionally known means. And Si
When the film and the C film are made to be amorphous, they may be heated at room temperature or higher, or they may be heated by using the heat of sputtering when forming a base film formed directly on the C film. You may. By heating the Si film and the C film, a stable amorphized film can be formed.

[0012]

In the magnetic recording medium of the present invention, the amorphized film formed by the Si film and the C film is extremely stable and prevents diffusion of gas and ions from the non-magnetic substrate, and directly above it. The underlying film can be surely protected. Further, by stabilizing the underlayer film, it is possible to stabilize the magnetic film located immediately above it, which does not adversely affect the magnetic film and has an extremely high coercive force as a magnetic characteristic of the magnetic film. By ensuring this, the magnetic recording density can be improved. Moreover, since the Si film is formed on the non-magnetic substrate and the C film is formed thereon to make it amorphous, even if excess Si remains after being made amorphous, the non-magnetic substrate side Since it is present in the film, it does not affect the characteristics of the base film.

[0013]

EXAMPLES Examples of the present invention will be shown below.

[Examples 1 and 2 and Comparative Examples 1 and 2]: An amorphized film (Si film + C film), a base film, a magnetic film, and a protective film are sequentially formed on a nonmagnetic substrate by a normal sputtering method. A magnetic recording medium of Examples 1 and 2 was manufactured by forming a film and applying a perfluoropolyether lubricant on the uppermost surface, and B-shift was measured as an index of high density, and the results are shown in Table 2. still,
Table 1 shows the composition of the non-magnetic substrate and various films. The B-shift measurement conditions were a thin film head having a gap length of 0.35 μm and a track width of 6.9 μm, and a flying height of 2.5 microinches and a radius of 20 mm. The modulation code is M.I. F. M. The recording pattern was evaluated by B6D9. On the other hand, as for the magnetic characteristics, a 7 mm square sample was cut out from each disk, and coercive force (Hc), remanent magnetization * film thickness (Br
δ) and squareness ratio (S ^* ) were measured. In Table 1, the film forming temperatures of various films are measured by a radiation thermometer, and the amorphous film is set to room temperature or 100 ° C. or lower, and the undercoat film is set to 100 to 600 ° C., preferably The temperature was set to 200 to 500 ° C. For the magnetic film, preheating at the time of depositing the base film was used. Further, the magnetic recording media of Comparative Examples 1 and 2 having the same structure except that the amorphized film was not provided were manufactured, and the same test was performed.

[0015]

[Table 1]

[0016]

[Table 2]

[Examples 3 and 4 and Comparative Examples 3 and 4] The same as Examples 1 and 2 except that the Co ₈₁ Cr ₁₃ Pt ₆ film 450Å was used as the magnetic layer. Table 3 shows the results of manufacturing the magnetic recording medium and performing the same test.
Further, magnetic recording media of Comparative Examples 3 and 4 having the same structure except that the amorphized film was not provided were manufactured, and the same test was performed.

[0018]

[Table 3]

[0019]

As described above, the magnetic recording medium of the present invention has magnetic characteristics suitable for high density recording.

Further, the film amorphized by the Si film and the C film improves the adhesion to the non-magnetic substrate, prevents gas or ions from diffusing from the non-magnetic substrate, and is amorphized. Since the film comes into contact with the base film, the base film and the magnetic film are laminated in a form capable of exhibiting their performance.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing a magnetic recording medium of the present invention.

Claims (4)

[Claims] 1. A magnetic recording medium having a non-magnetic substrate, a base film, a magnetic film, a protective film and a lubricating film as a basic structure, which is formed between a non-magnetic substrate and a base film on the non-magnetic substrate side. Done Si
A magnetic recording medium comprising a C film which is made amorphous by a film. 2. The magnetic recording medium according to claim 1, wherein the non-magnetic substrate is a glass or carbon-based substrate. 3. The magnetic recording medium according to claim 1, wherein the underlayer film contains Cr as a main component. 4. An amorphous film is formed from the Si film on the non-magnetic substrate side by forming a Si film and a C film on the non-magnetic substrate. A method of manufacturing a magnetic recording medium, characterized in that a base film, a magnetic film, a protective film, and a lubricating film are formed on the surface.