JPS6378317A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To maintain stable contact with a head at the time of high-density recording and to obtain a good signal to noise ratio by disposing a thin plasma- polymerized fine particle film and lubricating film on a thin ferromagnetic metallic film. CONSTITUTION:A perpendicularly magnetized film 9 consists of Co-Cr (79wt% Co) formed by a high-frequency sputtering method to 0.16mum thickness and the coercive force in the perpendicular direction thereof is 630(Oe). The thin plasma-polymerized fine particle film 10 of polyamide is formed thereon at a high frequency of 13.56(MHz) by using gaseous argon as a carrier gas. The lubricating layer 11 of stearic acid amide is further formed thereon to about 46Angstrom . Since the cushion effect of the polymerized fine particles and the durability of the polymerized fine particles by the adhesion thereof as the film to the thin ferromagnetic metallic film are good, the characteristic to maintain the front surface shape of the magnetic head by the high-speed sliding contact with the magnetic head is improved and the contact state of the small spacing loss is stably obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording medium whose magnetic recording layer is a ferromagnetic metal thin film suitable for high-density magnetic recording.

Conventional technology Recent advances in recording technology have significantly improved the recording density per unit area, and the practical use of magnetic recording media such as vapor-deposited tapes whose magnetic recording layer is a ferromagnetic metal thin film with an extremely smooth surface is rapidly increasing. It is becoming desired.

Therefore, there is a growing recognition that future increases in density will be premised on realistic solutions to tribological issues related to understanding friction, wear, etc. that occur when magnetic heads and magnetic recording media slide [Television Society of Japan] Magazine, VOL, 40. A6
(1986) 472 pages].

FIG. 2 is an enlarged sectional view of a conventional magnetic recording medium. Second
In the figure, 1 is a polyester film.

2 is a magnetic recording layer such as a Go-Ni-0 obliquely deposited film or a Co-Cr perpendicularly magnetized film;
is a top coat layer, 4 is a protective layer, and 5 is a lubricating layer.

Conventionally, the top coat layer has been expected to play a role as a protective layer, as disclosed in Japanese Patent Application Laid-open No. 113303/1982, which improves wear resistance by depositing a fatty acid metal salt film.
A sputtered film of a polymer having an imide group as disclosed in Japanese Patent Application Laid-open No. 7-116771, an example of sputtering using a polymer compound as a target as disclosed in Japanese Patent Application Laid-Open No. 58-77031, carbon, BN, MoS2.5in.
Examples of thinning the film by sputtering or vapor deposition, examples of using a diamond-like hard carbon film (Japan Society of Applied Magnetics, No. 46)
Materials from the 2017 Study Group) are known.

In addition, as a layer for lubricating purposes, fatty acids, fatty acid amides, etc. are deposited by vapor deposition, wet coating, etc. (for example,
30609) have been tried.

However, the above-mentioned examples are wear resistance and running properties.

Since the anti-corrosion effect cannot be fully satisfied, the idea of laminating layers and dividing the roles of each layer is increasing.

One in which a fluorocarbon-based lubricating layer is provided on an adsorption layer of a fatty acid metal salt (Japanese Patent Application Laid-Open No. 120331/1982), and one in which a fluorine-containing lubricating oil layer is provided on a hard carbon layer (Japanese Patent Application Laid-Open No. 126627/1982). Public.

(report), a lubricant layer formed on the 5i-N-0 thin film (
JP-A No. 61-131231), etc.

Problems to be Solved by the Invention However, while the above configuration improves durability, it becomes difficult to maintain stable contact with the head during high-density recording, and as a result, sufficient signal pairing cannot be achieved. Noise ratio (SIN
) is no longer obtainable, and improvements are desired for the practical application of high-density magnetic recording. 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 with small spacing loss, which is important for short wavelength recording.

Means for Solving the Problems In order to solve the above-mentioned problems, the magnetic recording medium of the present invention has a plasma polymerized fine particle thin film and a lubricating film disposed on a ferromagnetic metal thin film.

Function The magnetic recording medium of the present invention has the above-described structure, and has a cushioning effect of the polymeric particles, and the durability of the polymeric particles is good due to the fact that they are bonded to a ferromagnetic metal thin film as a film, so that they can be used at high speeds with the magnetic head. Since the maintenance of the front surface shape of the magnetic head is improved by sliding contact, a completely stable contact state with small spacing loss can be obtained.

EXAMPLES Below, the magnetic recording medium of the present invention will be explained with reference to the drawings. FIG. 1 is an enlarged sectional view of the magnetic recording medium of the present invention. In Figure 1, e is a polymer film made of polyethylene terephthalate film with a thickness of 11 μm, 7 is a 9-layer earthworm-shaped undercoat of water-soluble polymer, and the maximum roughness is 1.
It was set at 308.

Reference numeral 8 denotes a base layer consisting of a 400 μm thick titanium thin film formed by electron beam evaporation, and 9 a 0.16 μm thick Go-Cr (Co7swt%) film formed by high-frequency sputtering.
) The perpendicularly magnetized film has a perpendicular coercive force of 630 (Oθ). 1o is a thin film of plasma-polymerized fine particles of polyamide, the monomer is polyamide, argon gas is used as a carrier gas, and plasma is generated by a high frequency of 13.56 (MIIZ). Repeated experiments using monomer flow rate and discharge power as parameters resulted in an average of 106 particles/-0 average particle diameter e.
oo people.

10 under the condition that the particle height is 300 people and the polymer film thickness is 180 people.
form the ratio. 11 is a lubricating layer of about 46 layers of stearic acid amide formed by vacuum deposition.

A magnetic tape of 8 mm width with such a configuration has a gap length o,
Using 16μm ferrite head, track width 16μm
A rectangular wave with a bit length of 0.19 μm was recorded at m, and the overall relative reproduction error rate was compared. The error rate when recording and reproducing was assumed to be 1 under the conditions of 20° C. and 60% RH, and the magnification was compared.

The error rate during the 50th playback at 40°C and 80%RH is 1.22 to 1.31°, and the error rate during the 800th playback at 5°Cso%RH is 1.14 to 1.19, which is stably low. The value was shown.

Furthermore, when the same tape is recorded and reproduced using an amorphous sputter type head with a carrier signal length of 0.75 μm and a total gap length of 0.27 μm, the SIN is 51 (dB) and 4
o''Cso%RH, 5°C 80%RHT repeated playback, 620th playback S/'N is 60.6 ~ 51.2,5
It was extremely stable at 0.5 to sO89 (dB).

In the above embodiments, the polymer film is made of polyethylene terephthalate, but it may also be made of polyethylene naphthalate, polyphenylene sulfide, polyamideimide, polyimide, polycarbonate, or the like.

The undercoat layer may be a fine particle coating layer, a layer containing particles in earthworm-like protrusions, or may not necessarily be provided.

It is not an essential requirement for the underlayer to be non-magnetic.

Soft magnetic properties can be provided as needed, depending on the manufacturing method,
The material is also free.

Ferromagnetic metal thin films include Co-V, Co-Mo, and C, regardless of the easy magnetization direction, such as a perpendicular magnetization film or an in-plane magnetization film.

-O, Go-Ti, Co-Mg, Go-Rh
, Go-Pt.

Go-P, Go-Ni-0, Co-Ni-0r
, Go-Ni-P, etc., and the manufacturing method can be selected as appropriate.

The plasma-polymerized fine particle thin film may be formed using the same monomer T, or the fine particles and the thin film may be made from different types of monomers. Since the micronization conditions differ depending on the monomer, the conditions should be optimized as appropriate.

The monomer that can be used is fluorinated polyethylene.

Fluorocarbons such as polytetrafluoroethylene.

Chlorofluorohydrocarbons such as polychlorotrifluoroethylene, polyvinylidene fluoride.

Fluorohydrocarbons such as polyvinyl fluoride.

Hydrocarbons and the like are not particularly limited.

Regarding the lubricant layer, the material and manufacturing method can be freely selected, such as commercially available lubricants, modified lubricants, or synthetic lubricants.

Effects of the Invention As described above, the present invention has the excellent effect of being able to maintain good S/N and error rate in high-density magnetic recording even after repeated use from the beginning.

[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. 6... Polymer film, 7... Undercoat layer, 8... Base layer, 9... Ferromagnetic metal thin film, 10... Plasma polymerized fine particle thin film, 11
......Lubricating layer.

Claims (1)

[Claims] A magnetic recording medium characterized in that a plasma polymerized fine particle thin film and a lubricant film are disposed on a ferromagnetic metal thin film.