JPH0766513B2 - Magnetic recording medium - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium such as a magnetic tape or a magnetic disk suitable for high density magnetic recording.

2. Description of the Related Art Advances in high density magnetic recording have been remarkable, and they have been maximized by using a coating type magnetic layer in which ferromagnetic particles are dispersed in a crystallizing agent. Depending on the layered medium, higher densification is expected.

On the other hand, it is necessary to solve the problem of the interface between the head and the medium, which is centered on the stabilization of high-speed sliding between the magnetic head and the magnetic recording medium as a premise of increasing the density.

From the perspective of the magnetic recording medium, the durability and magnetic conversion characteristics, in particular, not only signal output but also noise (hereinafter referred to as S / N)
It is important to harmonize the improved characteristics of the above in a high level, and the method of partially oxidizing the ferromagnetic metal thin film, the method of finely roughening the magnetic recording layer, the method of providing a protective film, etc. Considered (eg, US Pat. No. 4,564,549, US Pat. No. 4,565,734).

Problems to be Solved by the Invention However, in the above configuration, the recording wavelength is 0.8 μm.
There is a system that can be put to practical use if the degree is 0.7 to 0.3 μ.
As the wavelength becomes shorter, such as m, sufficient S / N cannot be secured, so improvement is desired.

The present invention has been made in view of the above circumstances, and provides a magnetic recording medium capable of giving a sufficient S / N at a short wavelength.

Means for Solving the Problems In order to solve the above-mentioned problems, the magnetic recording medium of the present invention has a thin film magnetic recording layer composed of columnar crystal grains on a polymer film, and the surface of the columnar crystal grains. , Which is covered with a carbon thin film.

The magnetic recording medium of the present invention has the above-described configuration, which can significantly reduce the frictional resistance when the magnetic layer and the magnetic head slide, and unlike the case where the magnetic layer is separately provided as a protective film, the magnetic recording medium is coated with crystal particles. Since the thickness of the carbon thin film can be reduced, the spacing loss is reduced and a good S / N can be provided.

Examples Hereinafter, examples of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an enlarged cross-sectional view of a magnetic recording medium according to an embodiment of the present invention, in which 1 is a polymer film such as a polyethylene terephthalate film having a thickness of 9.5 μm, and 2 is columnar crystal fine particles coated with a carbon thin film. Magnetic recording layer consisting of 3
Is a lubricating layer.

FIG. 2 is a schematic cross-sectional view of columnar crystal fine particles.
Is the part of the columnar crystal grains, which is the part that becomes magnetized. 5
Is a first carbon thin film, 6 is a second carbon thin film, and 5 on the side contacting the magnetic head is preferably a diamond-like hard carbon (hereinafter referred to as DLC film) film as described later. What is not essential is that it consists of a carbon thin film and
This is because the magnetic recording medium may be configured by separately disposing the DLC film.

FIG. 3 is a schematic view of an essential part of an example of a vapor deposition machine used for manufacturing the magnetic recording medium of the present invention. In the figure, 7 is a vacuum chamber, 8 is a vacuum exhaust system 9, and a vacuum chamber 9 is used. Configured to be kept at. 10 is a polymer film, 11 is an unwinding shaft, 12 is a winding shaft, and 13 is a cooling can, which rotates in the direction of arrow F. 14 is an electron beam evaporation source, 15 is a limited vapor flow, 16 is a plasma tube made of tempered glass, 17 is a plasma injection hole, 18 is an external high-frequency excitation coil, 19 is a mesh electrode, with respect to the substrate, It is configured to be kept at a positive potential.
20 is a gas introduction hole.

A magnetic recording medium of this example was manufactured using the apparatus shown in FIG.

As a polymer film, a polyethylene terephthalate film having a thickness of 9.5 μm was used, and Co—Ni (Ni: 20 wt%) was electron beam evaporated. The minimum incident angle is 40 degrees and the film thickness is 0.16
It was controlled to μm. At the time of vapor deposition, carbon plasma was generated from a plasma tube for irradiation. Ar and methane 1: 1
Was introduced at a rate of 13.56 MHz, excited at a high frequency of 13.56 MHz, energy was applied to the carbon, and irradiation was performed under the condition that diamond-like hard carbon was formed at the minimum incident angle portion of vapor deposition. The DLC film was about 110Å. 19 kept at 1200V.

About 60 vapor-deposited film of perfluorobehenic acid is deposited on this vapor-deposited film.
Å I distributed it. The comparison tape is DL
Instead of the C film, an oxide film of Co and Ni (surface oxide layer thickness 150Å) is arranged on the surface of the columnar crystal particles to form a magnetic recording layer.
Tape A was prepared by arranging about 60Å perfluorobehenic acid on the surface, tape B was prepared by laminating about 100Å DLC film, and tape B was prepared by laminating about 60Å perfluorobehenic acid.

The S / N when recording a wavelength of 0.6 μm is 0 (dB) in this embodiment.
Then, the comparison tape A is -1 (dB) and the tape B is -3.
It was (dB). Regarding the S / N decrease with repeated use, at −5 ° C., 100 times and 200 times, the present example shows −0.4 (d
B), -0.5 (dB), but the comparative tape A is -4.8
(DB), -5.1 (dB), Tape B: -4.4 (dB), -4.
It was 5 (dB). At 40 ° C. and 5% RH, the S / N after repeated use 300 times is −0.9 (dB) in this embodiment, and the tape A is −6.
It was 4 (dB) and -4.5 (dB) for tape B.

In the examples, a polyethylene terephthalate film was used as the polymer film, but polyimide, polyamideimide, polyphenylene sulfide, polyethylene naphthalate, or the like may be used, or a fine particle coating layer, an earthworm-like ridge layer, or the like may be arranged.

Columnar crystal fine particles coated with carbon include Co-F and Co-F.
e, Co-Ag, Fe-Ag, Co-Cr, Co-Ce, Co-Ca, Co-Sm, Co-T
i, Co-W, Co-Mo, Co-Mg, Co-Ni-Zr, Co-Ni-Nb, Co-Cr
-Nb or the like may be used.

EFFECTS OF THE INVENTION As described above, according to the present invention, a good S / N ratio can be obtained in short wavelength recording.
It has an excellent effect that it can be used repeatedly while maintaining.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of a magnetic recording medium according to an embodiment of the present invention,
FIG. 2 is a schematic cross-sectional view of carbon-coated columnar crystal fine particles, and FIG. 3 is a cross-sectional configuration diagram of a main part of an example of a vapor deposition apparatus used to manufacture a magnetic recording medium according to an embodiment of the present invention. 1 ... Polymer film, 2 ... Magnetic recording layer, 4 ... Core part, 5 ... Carbon thin film, 6 ... Carbon thin film, 10 ... Polymer film, 14 ... Electron beam evaporation source, 16 ... Plasma tube,
18 …… High frequency excitation coil.

Claims (1)

[Claims] 1. A magnetic recording medium characterized in that a thin film magnetic recording layer comprising columnar crystal grains is arranged on a polymer film, and the surface of the columnar crystal grains is covered with a carbon thin film.