JPS63102016A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To eliminates the deposit on a magnetic head and to improve running durability by providing a protective film essentially consisting of graphitic carbon contg. <=10wt% one kind selected from Ge, Pd, Pt, and Zr on a thin film. CONSTITUTION:The protective film essentially consisting of the graphitic carbon contg. one kind selected from Ge, Pd, Pt, and Zr is provided on the thin film. The weight of the Ge, Pd, Pt, and Zr to be incorporated into the protective film is preferably 0.5-5%. The film which is formed of a ferromagnetic metal such as Fe, Co or Ni or ferromagnetic alloy such as Fe-Co or Fe-Ni or is formed by adding a slight amt. of metal elements, etc., thereto is used for the thin magnetic metallic film. The formation of a magnetic recording medium is executed by first depositing the thin magnetic metallic film on a nonmagnetic substrate and forming the protective film essentially consisting of the graphitic carbon contg. at least one kind among Co, Fe and Ni thereon. The thickness of the magnetic film is specified to 0.1-2mum and the thickness of the protective film to about 50-200Angstrom .

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording medium, and more particularly to a metal thin film type magnetic recording medium that has excellent running durability.

[Conventional technology]

In recent years, as the density of recording media has increased, so-called metal thin film magnetic recording media have been attracting attention in place of conventional coated magnetic recording media.

However, metal thin film magnetic recording media generally have poor running durability because it is difficult to mix lubricants or abrasives into the magnetic layer unlike conventional coated magnetic recording media. In the case of a perpendicular magnetic recording disk provided with a disk, adhesion occurs between the alloy layer on the surface and the head after about 100 running passes, and the disk often becomes unable to run.

In order to solve this problem, it has been proposed to apply a liquid lubricant to the surface of the magnetic thin film, or to provide a solid protective film on the surface of the magnetic layer.

Among these, it is known that providing a protective film mainly composed of carbon, which is a solid lubricant, on the surface of the magnetic thin film is particularly effective in improving running durability.

However, even if such a protective layer containing carbon as a main component is provided on the surface of the magnetic layer, running durability is still insufficient. This is thought to be mainly due to the fact that the deposits formed on the head increase the coefficient of friction with the protective film.

Furthermore, it has been proposed to incorporate boron, silicon, transition metal elements, etc. into the diamond-like carbon protective film (Japanese Unexamined Patent Publication No. 60-22236), but the lubricity is poor and therefore sufficient durability cannot be obtained. I can't do it.

[Problem that the invention seeks to solve]

The present invention provides a metal thin film magnetic recording medium that does not cause deposits on a magnetic head and has significantly improved running durability.

[Means for solving problems]

The present invention provides a magnetic recording medium in which a magnetic metal thin film is provided on a non-magnetic substrate, in which the main component is graphitic carbon containing at least one selected from Qe, Pd, Pt, and Zr on the thin film. The present invention relates to a magnetic recording medium characterized by being provided with a protective film.

The above-mentioned protective film containing graphite-like carbon as a main component means a graphite-like amorphous film prepared by a vacuum evaporation method, a sputtering method, or the like. That is, X
It is a film in which no clear peak is observed by line diffraction, and the plasmon loss coefficient of carbon determined by X-ray electron spectroscopy (XPS) is similar to that of graphite.

The weight of Ge, Pd%pt, and Zr contained in the above-mentioned protective film mainly composed of graphitic carbon is 10%.
% or less, and 0. It is preferably j-7%.

The magnetic metal thin film of the present invention includes ferromagnetic metals such as pe, Co, and Ni, or Fe-Co, Fe-Ni, and Co-Ni.
, Fe-8i%Co-Cr.

Co-V, Co-8m, Co-Pt5Co-P.

Ferromagnetic alloys such as Co-N1-P, )'e-Cr-Co,
Alternatively, those to which trace amounts of metal elements or the like are added are used.

As the non-magnetic substrate, it is possible to use film-like polymeric materials such as polyethylene terephthalate, polyimide, polyamide, etc., disc-shaped polymeric materials such as polycarbonate, polymethyl methacrylate, ceramics such as glass, metals such as aluminum, etc. The shape of the substrate may be a sheet, card, disk, drum, tape, or the like.

To create the magnetic recording medium of the present invention, a magnetic metal thin film is deposited on a non-magnetic substrate by vacuum evaporation, sputtering, ion blasting, plating, etc., and then C□ , pe.

A protective film mainly composed of graphitic carmen containing at least one type of Ni may be formed by vacuum evaporation, sputtering, or the like.

In this case, the magnetic film may be of a different type using two different magnetic materials, or may be of a single layer type with an underlayer provided. Alternatively, a laminated type having an intermediate layer may be used. In any case, the appropriate thickness of the magnetic film is O0/-2 .mu.m.

In addition, if the thickness of the protective film is too thick, sufficient output cannot be obtained during recording and reproduction, and if the force is too low, no improvement in running durability can be seen.
It is about 00 holes.

〔Example〕

Examples of the present invention will be described below.

A polyimide film with a thickness of SO μm was used as a nonmagnetic substrate.

First, a CoCr film with a thickness of 2300 holes was deposited on this substrate by sputtering in Ar gas with CoCr as a target.
A thin film was formed.

Next, a pellet of Ge, Pd, Pt, Zr, etc. is placed on the graphite target and sputtering is performed in Ar gas to deposit Ge on the CoCr thin film.

Various types of protective films having a thickness of λ00^ and having graphite-like carbon as a main component containing at least one of Pd, Pt, and Zr were prepared.

Process these into a disc shape with a diameter of 3.3 inches,
It was incorporated into a commercially available disc jacket.

After recording on a commercially available 70 disk drive, monitor the playback signal and friction coefficient.
The running durability was tested by rotating at speeds p and m and measuring the -ξ error until the friction coefficient suddenly increased.

The content of Ge, Pd, Pt, Zr, etc. was determined from the differential of each element and carbon measured using Auger electron spectroscopy based on the Kutle peak ratio. It was also similarly confirmed that there was no change in the composition of the constituent elements of the protective film in the film thickness direction.

For comparison, a medium with a protective film having a thickness of 200 holes mainly composed of graphitic carbon containing no Ge, Pd, Pt, Zr, etc. was also prepared, and this was used as a comparative example.

The results obtained are shown in Table 1 to Table μ. As is clear from the table, the running durability of the media provided with a protective film mainly composed of carbon containing appropriate amounts of the above metals is higher than that of the media provided with a protective film mainly composed of carbon that does not contain these metals. Excellent.

As a result of observing the heads under a microscope, media with high metal content and poor running durability had no deposits but were scratched, while media with excellent running durability had no deposits or scratches.
Although there were no scratches on the medium that did not contain metal, it was confirmed that deposits were generated.

Table 1 Table 2 Table 3 Table μ Table 1 [Effects of the Invention] The magnetic recording medium of the present invention does not produce deposits on the magnetic head during running, and at the same time has significantly superior running durability. It is something.

Patent applicant: Fuji Photo Film Co., Ltd. -7θ-

Claims (1)

[Claims] A magnetic recording medium comprising a magnetic metal thin film provided on a non-magnetic substrate, the main component of which is graphitic carbon containing 10% by weight or less of at least one selected from Ge, Pd, Pt, and Zr. A magnetic recording medium characterized by being provided with a protective film.