JPH03116520A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a magnetic recording medium having high C/N and high durability in good balance by providing island-like deposites of one of Al, Ti, Si, W, Mo, and B on a smooth ferromagnetic metal thin film, and further providing a diamond-like hard carbon thin film thereon. CONSTITUTION:Island-like deposites 3 comprising one of Al, Ti, Si, W, Mo, and B are formed on a smooth ferromagnetic metal thin film 2, and further a diamond-like hard carbon thin film 4 is provided thereon. By this constitution, microscopic uniformity of the ferromagnetic metal thin film 2 can be improved to improve the noise level and C/N compared to a conventional medium when same spacing loss is considered. Since the hard diamond-like carbon film firmly adheres with island-like deposites of Al, etc., as cores to the film 2, a pattern of small roughness height with little variation in shape can be formed to improve durability of the medium. The obtd. medium shows good balance of high C/N and high durability.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording medium suitable for high-density magnetic recording.

BACKGROUND OF THE INVENTION Improving magnetic recording density continues to be a fundamental requirement and is achieved on the basis of narrower tracks and shorter wavelengths. Nowadays, due to the practical use of vapor-deposited tape (2), there are no white clips in the high band 8mm specification.
．． Wavelengths are being shortened to the level of less than 4 μm. The vapor-deposited tape uses a Co-Ni-0 obliquely vapor-deposited film as a magnetic recording layer.To ensure durability, the base film is given a shape and fine irregularities are formed on the obliquely vapor-deposited film [e.g. Technology June 1989 issue, 2
See page 8].

Problems to be Solved by the Invention However, when the structure described above is used for recording and reproducing in a wider band and shorter wavelength range, there is a problem that sufficient C/N and durability cannot be ensured, and improvements have been desired. .

The present invention was made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a magnetic recording medium that maintains a higher level of balance between C/N and durability.

Means for Solving the Problems In order to solve the above-mentioned problems, the magnetic recording medium of the present invention comprises:
Island-shaped AI on a smooth ferromagnetic metal thin film! .

One of Ti, Si, W, Mo, and B is placed on top of which a diamond-like hard carbon film is placed.

Function: Due to the above-described structure, the magnetic recording medium of the present invention has good microscopic uniformity of the ferromagnetic metal thin film, improves noise, and improves C/N when compared under the same spacing loss conditions. Also, the durability is due to island-shaped AI! This can be improved by firmly adhering a hard diamond-like carbon film to the core and forming irregularities with small changes in shape.

EXAMPLES Below, the magnetic recording medium of the present invention will be explained with reference to the drawings.

(Example 1) FIG. 1 is an enlarged sectional view of a magnetic recording medium according to an example of the present invention. In FIG. 1, reference numeral 1 denotes a substrate made of a polymer film such as polyethylene terephthalate, polyethylene naphthalate, polyether ether ketone, or polyimide, or an A1-Mg alloy plate. The surface preferably has an average roughness of 10 to 40 roughness, and a maximum roughness of 30λ to 70 roughness. 2 is Co-0, Co-Ti, Co-Cr, Co-Ta
.

Co-Mo, Co-W, Co-N i, Co-N i-
A ferromagnetic metal thin film such as O, Co-Cr-Nb, etc. may be formed by a sputtering method, an electron beam evaporation method, etc., and if necessary, ion irradiation treatment may be performed or an underlayer may be provided. 3
are AI, T i, S i, and W.

An island-shaped metal made of either Mo or B may be formed by electron beam evaporation, ion plating, sputtering, or the like. 4 is a diamond-like hard carbon film, C
, J (may be formed by any method such as accelerating gas plasma, carbon ion irradiation, or sputtering using graphite as a target. 5 is a fatty acid.

This is a lubricant layer in which necessary amounts of fatty acid amide, perfluoropolyether, etc. are applied by vacuum deposition, solution coating, etc. The present invention may be implemented in either tape or disk form.

Examples of the present invention will now be described in more detail in comparison with comparative examples.

Polyethylene terephthalate film with a thickness of 40 μm (
A Co-Cr (9wt% Conia) perpendicularly magnetized film was formed to a thickness of 0.2 μm on the average roughness of 20 mm and maximum roughness of 50 mm using a sputtering method, and an island-like metal was placed on top of it using the same high-frequency sputtering method. Then, on top of that, target graphite, Ar + H = 0 2 03 (To
rr), Ar:H=1:2. 13.56
(MHz), 0.8 (kW) to form a diamond-like hard carbon film, and as a lubricant, "Fomblin Z" manufactured by Montegisson, which is commercially available as perfluoropolyether, was used.
-25" was coated with 1.0 [■/-] to obtain a 5-inch floppy disk. In some of the comparative examples, before the Co--Cr perpendicular magnetization film was applied, Si 02 with a diameter of 150" A material containing 50 particles/μ was used.

A 0.38μm head with a 0.2μm gap length and a sendust sputtered film placed in the gap between each disk.
A track of 10 μm is recorded at a wavelength of m, and the reproduction C/
Table 1 summarizes the conditions and evaluation results of the 1-0 medium for comparison of N. From Table 1, the present invention has Ai', T
Compared to i, W, Mo, Si, and B, which have good durability due to strong bonding with carbon, Sb, Pt, Cr, etc. have insufficient durability due only to the shape effect of the structure, and are relatively The initial C/N is 2.7 to 2.8 (d
B) It can be seen that it has been improved and has the same durability.

(Left below) (Example 2) Another means to solve the problem is to create a diamond-like hard carbon film on a smooth ferromagnetic metal thin film through either textured high-density polyethylene or polyurethane. It is arranged so that

The magnetic recording medium of the present invention has the above-described structure.

The microscopic uniformity of the ferromagnetic metal thin film is better, the noise is improved, and the C when compared under the same spacing loss condition.
/N improves. Furthermore, durability is greatly improved by the unevenness of the texture, the large adhesion strength obtained from the combination of materials, and the cushioning effect of the polymer.

FIG. 2 is an enlarged sectional view of a magnetic recording medium according to a second embodiment of the present invention. In FIG. 2, components that need only be selected from the same group as in FIG. 1 are given the same numbers. 6 is high-density polyethylene placed on a smooth ferromagnetic metal thin film;
It is a thin film with any texture of polyurethane, and the film thickness is preferably up to 200 layers, and the texture does not necessarily have to be the same in the disk shape and the tape shape, and is not particularly limited.

More specifically, examples of the present invention will be explained in comparison with comparative examples.

10 μm thick polyethylene terephthalate film (
Co-Ni (Co: 80
wt%) in oxygen at 5 x 10-5 (Torr) at a minimum incident angle of 40 degrees with 1000 people, followed by 1000 people in the same way, and a total of 2000 people deposited a Co-Ni-0 obliquely deposited film. A resin coat is applied on top of it using a solution coating method, and after drying, using abrasive paper, the width of the groove is 5 to 10 μm, and each pitch is 1.
A groove of 50 to 200 μm was formed (the groove extended in the longitudinal direction of the tape), and CH4 gas was poured onto it at 13.56 μm (
MHz) to form a plasma using high frequency waves, forming a diamond-like hard carbon film, and depositing Denipon's KRYTOX on top of the diamond-like hard carbon film.
0.9 (■#) of 143AC was applied to make a tape with a width of 8 mm.

In some of the comparative examples, TiO2 fine particles having a diameter of 100 particles were arranged at 50 particles/μ2 before forming the Co-Ni-0 film.

Both the Example and the Comparative Example are of a laminated alloy type with a gap length of 0.2 μm, and recording and reproduction are performed with high band 8 mm specifications, and the C/N is
compared. The tape conditions and results obtained are shown in Table 2.

As can be seen from Table 2, high-density polyethylene and polyurethane exhibit durability, which is thought to be due to strong reaction adhesion with carbon, but the constituent requirements of resin, texture, and diamond-like hard carbon film alone are not sufficient. It shows what cannot be said.

It is also clear from comparison with other comparative examples that C/N and durability are balanced at a higher level.

(The following is a blank space) Effects of the Invention As described above, the present invention has the excellent effect of providing a magnetic recording medium having high density C/N and excellent durability.

[Brief explanation of drawings]

FIGS. 1 and 2 are enlarged cross-sectional views of magnetic recording media according to embodiments of the present invention, respectively. 1...Substrate, 2...Ferromagnetic metal thin film,
3... Island-like metal, 4... Diamond-like hard carbon film, 6... Thin film with texture.

Claims (2)

[Claims] (1) Islands of Al, Ti, and S on a smooth ferromagnetic metal thin film
1. A magnetic recording medium comprising one of i, W, Mo, and B on which a diamond-like hard carbon thin film is disposed. (2) A magnetic recording medium characterized in that a diamond-like hard carbon thin film is disposed on a smooth ferromagnetic metal thin film via either textured high-density polyethylene or polyurethane.