JPH01196716A - Magnetic recording medium and tape cassette - Google Patents

Abstract

PURPOSE:To improve the C/N in a short wavelength region and durability of a recording medium by subjecting a perpendicularly magnetized film to partial surface oxidation, then providing a protective lubricating layer thereon. CONSTITUTION:The perpendicularly magnetized film 2 of a Co alloy (e.g.: Co-Cr film) formed by a high-frequency sputtering method, etc., and the protective lubricating layer 4 formed by disposing a lubricating layer consisting of a fatty acid, etc., on a protective film consisting of a diamond-like hard carbon film via the partially surface oxidized film 3 are provided on a high-polymer film 1. The layer 3 is formed to a desired thickness and area by implantation of oxygen ions, etc., and can be formed to a spot, stripe or grid shape. The microprojections by the layer 3 are then formed and, therefore, the durability is improved and since the parts subjected to a spacing loss are concentrated to the layer 3, the C/N in the short wavelength region is assured.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording medium having a ferromagnetic metal thin film all-magnetic recording layer suitable for high-density magnetic recording, and a tape cassette incorporating the same.

Conventional technology The perpendicular magnetic recording method has less demagnetization at short wavelengths than the current longitudinal magnetic recording method, and its practical application is an important technology for the future development of magnetic recording. Improving practical characteristics has been taken up as a priority issue, and improvements are being considered.

In particular, ferromagnetic metal thin films such as Co-Or and Go-Or-Nb have poor abrasion resistance, and may be treated with lubricants such as metal soap or perfluoropolyether (Digest Op Intermagnetic).
of INTERMAG) 1985, EA
-10 (1985)), Method of forming Go-Or-0 protective film by sputtering method to improve wear resistance [No. 9]
Collected summaries of academic lectures of the Japan Society of Applied Magnetics, 268-11 (
1985)) etc. have been proposed.

Problems to be Solved by the Invention However, when a protective film is provided to improve wear resistance,
Even in the perpendicular magnetic recording method, the drop in short wavelengths due to spacing loss, which is the same as in the longitudinal magnetic recording method, is large, so it is recommended to make the protective film as thin as possible or improve the wear resistance of the magnetic recording layer itself. By doing so, the C/N in the short wavelength range
-i, and it is necessary to maintain durability within a practical range, and improvements have been desired.

The present invention was made in view of the above circumstances, and the C/N
The present invention provides a magnetic recording medium for perpendicular magnetic recording with improved durability and durability, and a tape cassette using the same.

Means for Solving All the Problems In order to solve the above-mentioned problems, the magnetic recording medium of the present invention has a CO-based alloy perpendicular magnetization film partially oxidized on the surface and a protective lubricant layer disposed on the surface. be.

Effect: Due to the above-described structure, the magnetic recording medium of the present invention has minute protrusions of oxidized portions formed on the perpendicularly magnetized film itself, which reduces friction and wear due to the sliding load on the other side, and improves durability. At the same time, the C/N ratio in the short wavelength range is ensured because the portions subject to spacing loss 2 are concentrated in the oxidized portions and other portions can be ignored.

EXAMPLE Hereinafter, an example of the present invention will be described in detail with reference to the drawings. The figure is an enlarged sectional view of a magnetic recording medium according to an embodiment of the present invention. In the figure, 1 is a polymer film made of polyethylene terephthalate, polyphenylene sulfide, polyether sulfone, polyetherimide, etc. If necessary, a film with nine undercoating layers such as a fine particle coating layer can also be used. 2 is Go-Or, Go-Mo,
Go-Ti.

Go-W, Go-Or-Wb, Co-N
G of i-Or etc.

A perpendicularly magnetized film of a perpendicularly magnetized alloy is formed by electron beam evaporation, high-frequency sputtering, io-y brating, etc.
, 05 μm to 0.3 μm thin film, 3 is a partial surface oxidation layer, the oxide layer needs to be thick to ensure durability, and thin to reduce spacing loss and improve stiffness. 100 to 200 people is preferable because of the large number of people involved, and the total area of the partial surface oxidized layer as viewed from the top is preferably about A to IA. In addition, the surface oxidation layer is
They may be scattered in the form of dots, stripes, or grids, and suitable processing methods include oxygen ion implantation, oxygen neutral beam implantation, and oxygen atom implantation. 4 is a protective lubricating layer, BN
A protective film such as a thin diamond-like hard carbon film or a plasma-polymerized film is coated with a lubricating layer made of fatty acid, perfluoropolyether, etc. It must be thin enough to minimize spacing loss, and material selection and manufacturing are required. It is preferable to examine and optimize the method and manufacturing conditions experimentally.

Hereinafter, one embodiment of the present invention will be described in more detail. G was applied onto a 10 μm thick polyethylene terephthalate film (average roughness: 26 mm, maximum roughness: 60 mm) using a high-frequency sputtering method.

-1r (Or: 20.4wt%) perpendicular magnetization film 11
500 people form oxygen atoms and oxygen ions at 1sK,
Oxygen atomic beam i4
Irradiated with ~5X10 atoms/-, oxide layer thickness 12
The oxide layer surface fraction was 24%, and the oxide layer shape was a stripe shape with a width of 50 μm arranged in a direction substantially perpendicular to the longitudinal direction of the tape. As a result of this treatment, the oxidized layer portion had an average of 50 protrusions.

Furthermore, on top of this, set the graph eye If target, person r + H2 = 7.2 X 1 0-' (Torr
) Person r:H2=1:4.1356 (Mada) 1.5
A diamond-like hard carbon thin film was formed by sputtering under the conditions of (KW), and on the soil was added "KRY" manufactured by DuPont, which is commercially available as perfluorocervonic acid.
TOX, 157FS-M'' was arranged with a dry thickness of 50 mm to make a magnetic tape with a width of 8 mm.On the other hand, the comparative example was co-Or-0.
160 protective films were formed by high frequency sputtering method, and the same 1. ; < ” KRYTOX 15 FS
The same conditions were used except that 60 ``-M'' tapes were distributed.The V characteristics of both tapes were compared using 8mm video tapes that had been completely modified.

A rectangular wave with a recording wavelength of 0.38 μm was recorded using a stacked amorphous head with a gap length o of 16 μm, and the reproduction G/Hf was compared. Initial C/N is Example 2o (dB)
Then, the comparative example was -s, 2 (dB). 40 again
When repeatedly driven at ℃85%RH, the playback output for the 60th time was 1(d) for all three video cameras compared to the initial value in the example.
B) However, in the comparative example, the playback output was 3.
On the 7th run, there was a phenomenon in which the power level decreased by 3 (dB) and the running became unstable.

As for the still characteristics, in the example, the time until noise became noticeable on the screen was 70 to 75 minutes, while in the comparative example it was 4 minutes.
It was 1 to 47 (minutes).

Effects of the Invention As described above, according to the present invention, the C/
N has the excellent effect of producing a durable magnetic recording medium.

[Brief explanation of the drawing]

The figure is an enlarged cross-sectional view of a magnetic recording medium in one embodiment of the present invention. 1...Polymer film, 2...GO-based alloy verticalization film 3...Partial surface oxidation layer. Name of agent: Patent attorney Toshio Nakao and 1 other person/
--Kimiko Ichigo Phil person? ---Co thread metal alloy perpendicular magnetization

Claims (2)

[Claims] (1) A magnetic recording medium characterized by having a Co-based alloy perpendicularly magnetized film partially oxidized on the surface and provided with a protective lubricant layer. (2) A tape cassette containing the magnetic recording medium according to claim 1 in the form of a tape.