JPH01320622A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve durability and drop-out performance by specifying the content of nitrogen atom in a diamond-like hard carbon film of the recording medium in which the carbon film is provided on a ferromagnetic metal film. CONSTITUTION:On a polymer film 4, a fine particle coating layer 5 incorporated with Al2O3, Zn O, etc., and the ferromagnetic metal film 6 consisting of Co-O, Co-Os, etc., are formed by high frequency sputtering. Then, the diamond-like hard carbon film 7 contg. 5 - 15 atomic % nitrogen atoms, and successively a lubricating layer 8 consisting of perfluorecarbonic acid are formed to consti tute the recording medium. If the content of nitrogen atom in the film 7 is <=5 atomic %, dropout may increase and still-durability may be deteriorated. On the other hand, if the content of nitrogen exceeds 15 atomic %, hardness and durability are lowered. Thereby, by specifying the content, the recording medium has good durability and drop-out property.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a magnetic recording medium having a magnetic recording layer made of a ferromagnetic metal thin film, including perpendicular magnetic recording suitable for high-density magnetic recording.

BACKGROUND OF THE INVENTION Magnetic recording has made remarkable progress in recent years, and magnetic recording media whose magnetic recording layer is a ferromagnetic metal thin film are on the verge of being put into practical use.

FIG. 2 is an enlarged sectional view of an example of a conventionally proposed magnetic recording medium having a ferromagnetic metal thin film as a magnetic recording layer. Second
In the figure, 1 is a polymer film of polyethylene terephthalate, polyphenylene sulfide, polyether ether ketone, etc., which may be provided with a fine particle coating layer, an undercoat layer, etc. as required. 2 is Go-Ni, Go
-Or, co-0° ferromagnetic metal thin film such as Go-Ti, Go-Ni-0, 3 is a plasma polymerized film, 5i02
This is a protective layer in which a film 1 etc. and a lubricant such as fatty acid or perfluoropolyether are laminated. [Unexamined Japanese Patent Publication No. 61-224128
No. 61-139919, Japanese Patent Application Laid-Open No. 1983-139919
-6426, etc.] The magnetic recording medium shown in Fig. 2, which has recently been particularly expected to be improved, has been improved in terms of durability by providing a hard protective film [JP-A-61-126627 Publication, JP-A-6'1
Publication No. 233412] At present, the film thickness is about 200 to ensure durability in consideration of spacing loss.

Problems to be Solved by the Invention However, in the above configuration, the recording wavelength is 0.6μ.
When the thickness is less than 200 m, there are problems such as the spacing loss is too large for a film thickness of 200 people, and the error rate in drop-out and digital recording becomes large depending on the location, and improvements have been desired. The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a magnetic recording medium that improves spacing loss, does not reduce durability, and also improves dropout.

Means for Solving the Problems In order to solve the above-mentioned problems, the magnetic recording medium of the present invention has a diamond-like hard carbon thin film arranged on a ferromagnetic metal thin film, and the diamond-like hard carbon thin film is made of nitrogen. The number of atoms has been increased from 5 to 15 atoms.

Due to the above-described structure, the magnetic recording medium of the present invention reduces the insulation properties of the diamond-like hard carbon thin film, making it difficult for high-speed sliding with the magnetic head and for the running system, although the hardness remains almost the same. The surface is charged due to friction, which causes noise, and dropouts due to foreign matter adhesion.

Since an increase in error rate can be prevented, dropout performance can be improved without reducing durability.

EXAMPLE Hereinafter, an example of the magnetic recording medium of the present invention will be described in detail with reference to the drawings. FIG. 1 is an enlarged sectional view of a magnetic recording medium according to an embodiment of the present invention. In Fig. 1, 4 is a polymer film such as polyamide, polyether ether ketone, polyether sulfon, polyethylene naphthalate, etc.;
Fio 2 , a fine particle coating layer containing polyethylene spheres, polyimide spheres, etc., and 6 is CO-◯.

Go-〇s, Go-Ti, Go-Or, Co
-Mo, Go-Ru.

Co-Ni, Co-Ni-P, Go-Ni
-0, Go-Or-Nb.

It is a ferromagnetic metal thin film such as Go-Or-Nd, and can be formed by electron beam evaporation, high frequency sputtering, ion beam deposition, ion blating, or the like. Ryo is a diamond-shaped hard carbon thin film containing 5 to 15 nitrogen atoms, and the film thickness is 50 to 1.
It is preferable that the group consist of 50 people. Such a thin film is
A method of generating a plasma of a mixed gas of hydrocarbon and ammonia gas and irradiating it at an accelerated rate, or targeting graphite, such as Mur + NH5, Mur + H2-1 - NH5.
It can be formed by sputtering using plasma of a mixed gas such as , etc. However, if the content of nitrogen atoms is less than 5 atoms, the insulation is still good and the humidity is low (
If the temperature exceeds 15 atoms, the hardness decreases and the durability of the film itself decreases, and the film thickness increases. The range is determined by the fact that the spacing loss increases, making it unsuitable for high-density recording. Reference numeral 8 is a lubricant such as perfluorocarboxylic acid, perfluoropolyether, or organosilicon compound, which is formed by a solution coating method, a vacuum evaporation method, or the like.

The configuration described above may be used in either a magnetic disk or magnetic tape format.

Hereinafter, more specific examples will be explained in comparison with comparative examples.

10 pieces/(μm)2 of 5i02 fine particles with a diameter of 100 on a polyethylene terephthalate film with a thickness of 12 μm
On top of that, diagonal vapor deposition is applied along a cylindrical can with a diameter of 1 m at an angle of incidence of 9Q to 40 degrees at s x 1o' (T
Go-Ni (Go, 80 wt%
) by 0.15 pm electron beam evaporation, and C
An o-Ni-0 film was formed. A diamond-shaped hard carbon thin film was placed on the above-mentioned film under different conditions, and 56 perfluorostearic acids were placed on top of it by vacuum evaporation, and it was processed into a magnetic tenip with a width of 8 mm. Each magnetic tape was evaluated using a modified 8 mm video.

The modification is to change the center frequency of the brightness signal from s (MHz) to 7
(MHz), with wideband specifications.

Diamond-like hard carbon thin film targets graphite, Ar and N)! The film was formed by high-frequency sputtering using a high frequency of 40 (MHz) by selecting a discharge gas in the combination of 5 and keeping the film thickness constant at 120 MHz.

The evaluation method is to visually evaluate still images at 40'C, 10% RH, and compare the time until noise becomes noticeable.For dropout, compare the average value and maximum value, and evaluate the dropout by 3 per minute.
(μ5ec), −1o (dB). The magnetic tape conditions and evaluation results are summarized in a table.

Effects of the Invention As described above, the present invention has excellent effects in that a magnetic recording medium with good durability and dropout performance can be obtained.

[Brief explanation of the drawing]

FIG. 1 is an enlarged sectional view of a magnetic recording medium according to an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of a conventional magnetic recording medium. 4...Polymer film, 6...Ferromagnetic metal thin film, 7...Diamond-shaped hard carbon thin film (nitrogen-containing).

Claims (1)

[Claims] 1. A magnetic recording medium comprising a diamond-like hard carbon thin film disposed on a ferromagnetic metal thin film, wherein the diamond-like hard carbon thin film contains 5 to 15 at% of nitrogen.