JPH0773434A - 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 an Si film and platinum group metallic film on a nonmagnetic substrate by a sputtering method, then siliciding the films to form silicided films and forming a ground surface film, magnetic film, etc., by a sputtering method right thereon. 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 film constituted of the platinum group element silicided by the Si film formed on the nonmagnetic substrate side or its alloy thereof 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 film silicided by the Si film and the platinum group metal film improves the adhesion property to the nonmagnetic substrate and prevents the diffusion of 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 so as to be integrated, and more specifically, a magnetic recording medium capable of improving the magnetic recording density and a method of manufacturing the same. 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 inventors have found a magnetic recording medium characterized by interposing a film (hereinafter, referred to as a silicidation film) composed of a platinum group element or an alloy thereof which is silicidized by an i 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.

The silicidation film is composed of a Si film and platinum group elements (Pt, Pd, Rh, Ir, Ru, Os).
Alternatively, it is obtained by sequentially forming a film composed of the alloy (hereinafter referred to as a platinum group metal film), and then heating the film if necessary. The silicidation rate between the Si film and the platinum group metal film varies depending on the heating temperature and the silicide composition, but is about 100 to 200 Å / m at the sputtering temperature (300 to 500 ° C.) in the actual operation.
It is about in. When Si reaches the uppermost portion of the platinum group metal film by diffusion, the entire platinum group metal film is silicified and becomes amorphous. Therefore, the thickness of the platinum group metal film (upper limit) ) Is the heating temperature in actual operation,
Also, it is preferable to set it to such a degree that the diffusion of Si can reach the uppermost portion of the platinum group metal film in the time period until the underlying film immediately above it is sputtered. Normally,
Its thickness is 50 to 1000Å. On the other hand, the thickness of the Si film is set to 20 to 1500Å, preferably 30 to 1000Å. When the thickness of the Si 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 nonmagnetic substrate becomes insufficient. Also, 150
When the thickness is 0 Å or more, the practical meaning is reduced and the productivity is reduced.

To manufacture the magnetic recording medium of the present invention, a Si film and a platinum group metal film are formed on a non-magnetic substrate by a sputtering method or other means to be silicidized, and a silicidized film is used as an intervening film. After forming, the underlying film, the magnetic film, the protective film, and the lubricating film are formed directly on the film by the sputtering method or other conventionally known means. When the Si film and the platinum group metal film are silicidized, they may be heated at room temperature or higher, or the heat of sputtering when forming an underlayer film formed directly on the platinum group metal film. You may heat using.
When the Si film and the platinum group metal film are heated to be silicidized, silicidation is promoted and a stable silicidized film can be formed.

[0012]

In the magnetic recording medium of the present invention, the silicidized film formed by the Si film and the platinum group metal film is extremely stable and prevents diffusion of gas and ions from the non-magnetic substrate,
Moreover, it is possible to reliably protect the underlying film immediately above it. 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 platinum group metal film is formed on the non-magnetic substrate for silicidation, even if excess Si remains after silicidation, it exists on the non-magnetic substrate side. Therefore, the characteristics of the base film are not affected.

[0013]

EXAMPLES Examples of the present invention will be shown below.

[Examples 1 and 2 and Comparative Examples 1 and 2]: A silicidation film (Si film + platinum group metal film), a base film, a magnetic film, and a protective film were formed on a non-magnetic substrate by an ordinary sputtering method. Films are sequentially formed, and a perfluoropolyether lubricant is applied to the uppermost surface to manufacture the magnetic recording media of Examples 1 and 2,
B-shift was measured as an index of densification and shown in Table 2. The constitutional contents of the above-mentioned non-magnetic substrate and various films are shown in Table 1. The B-shift measurement conditions were a thin film head with a gap length of 0.35 μm and a track width of 6.9 μm, a flying height of 2.5 micro inches, and a radius of 2
It was measured at 0 mm. The modulation code is M.I. F. M. The recording pattern was evaluated by B6D9. On the other hand, the magnetic characteristics are
A 7 mm square sample was cut out from each disk, and coercive force (Hc), remanent magnetization * film thickness (Brδ), and squareness ratio (S ^* ) were measured by a vibration type magnetic characteristic device (VSM). In Table 1, the film forming temperature of each film is measured by a radiation thermometer, and the silicidation film is at room temperature or 1
The temperature is set to 00 ° C or lower, and the base film is 100 to 600
The temperature was set to 0 ° C, preferably 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 exactly the same structure except that the silicidation film was not provided were manufactured, and the results of the same test are shown in Table 2.

[0015]

[Table 1]

[0016]

[Table 2]

[Examples 3 to 6]: Magnetic recording media of Examples 3 to 6 were manufactured in exactly the same manner as in Example 1 except that the Si film was changed to 1000 Å and the Pt film was changed to 20 to 1000 Å. The results of similar tests are shown in Table 3.

[0018]

[Table 3]

[Examples 7 and 8] Examples 7 and 8 are exactly the same as Examples 1 and 2 except that the Pt film is replaced with a Pd film.
Table 4 shows the results of manufacturing the magnetic recording medium of No. 1 and performing the same test.

[0020]

[Table 4]

[Examples 9 to 12] Magnetic recording of Examples 9 to 12 was carried out in exactly the same manner as in Example 1 except that the Pt film was replaced with another platinum group (Rh, Ir, Ru, Os) film. Table 5 shows the result of manufacturing the medium and performing the same test.

[0022]

[Table 5]

[0023]

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

Further, the film silicidized by the Si film and the platinum group metal film improves the adhesion to the non-magnetic substrate, prevents the diffusion of gas or ions from the non-magnetic substrate, and is amorphous. Since the silicidation film comes into contact with the underlayer film, the underlayer film and the magnetic film are laminated so that the performance can be exhibited.

[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 film made of a platinum group element or an alloy thereof which is silicided 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. A silicidation film is formed from the Si film on the non-magnetic substrate side by forming a Si film and a film made of a platinum group element or an alloy thereof on the non-magnetic substrate, A method of manufacturing a magnetic recording medium, characterized in that an underlying film, a magnetic film, a protective film, and a lubricating film are formed on the surface of the silicidized film.