JPH02116012A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve high-density recording characteristics by laminating an oblique vapor deposited film and perpendicularly magnetized film on a high- polymer film having granular projections and forming the oblique vapor deposited film to have the coercive force in the perpendicular direction thereof larger than the coercive force in the perpendicular direction of the perpendicularly magnetized film. CONSTITUTION:The oblique vapor deposited film 3 and the perpendicularly magnetized film 4 are laminated on the high-polymer film 1 having the granular projections and the coercive force in the perpendicular direction of the oblique vapor deposited film 3 is made larger than the coercive force in the perpendicular direction of the perpendicularly magnetized film 4. Co, Co-Ni, Co-Cr, Co-Ta, etc., are usable as the oblique vapor deposited film 3. The coercive force in the perpendicular direction thereof is preferably set larger by, preferably >=20% than the coercive force in the perpendicular direction of the perpendicularly magnetized film 4. The perpendicularly magnetized film 4 is a sputtering film or film deposited by evaporation with electron beams, etc., of Co-Cr, Co-Ti, Co-W, Co-Mo, Co-Cr-Nb, etc. The wide-band C/N is realized by the constitution improved in durability by the granular projections in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magneto-electric recording medium having a magnetic recording layer made of a ferromagnetic metal thin film suitable as a high-density magnetic recording medium.

Conventional technology In recent years, there has been remarkable progress in increasing the density of magnetic recording, and there is a limit to what can be achieved by thinning coating films and transitioning from iron oxide magnetic powder to alloy magnetic powder, and the question of whether longitudinal recording or perpendicular recording is being made. There are growing expectations for the practical application of magnetic recording media that have magnetic recording layers made of thin ferromagnetic metal thin films of high magnetic flux density materials [Foreign Journal, IER: E TRANSACTI]
ONS ONMAGNETIC8Vot, MAG-21
, 4-3, (198g) p, p, 1217-1220)
. Although magnetic recording media with such a configuration have excellent short wavelength recording performance, they have many problems with respect to the interface with the magnetic head, and improvements have been made in various fields. For example, JP-A-52-18770, JP-A-66-
As disclosed in Japanese Patent Laid-open No. 1.6937 and Japanese Patent Application Laid-Open No. 112431/1984, attempts were made to impart graininess to the surface of the magnetic recording layer using partially oxidized ferromagnetic metal thin films.
Conventional ferromagnetic metal thin films have problems with running properties and methyl properties, but improvements are being made. On the other hand, the protective layer becomes a factor of output loss as the wavelength becomes shorter, so it is not a preferable countermeasure, but the above-mentioned graininess alone is not sufficient, and efforts are being made to improve the effect with a minimum thickness [JP-A-61] -126627 Publication, JP-A-61-
151835].

To impart graininess to the surface of the magnetic recording layer, 5102. CaCo3. At2o3. Co and Co
-Ni by electron beam evaporation in an oxygen atmosphere or Co-Cr
, Co-0r-Nb, etc., are generally deposited by high-frequency sputtering to form the magnetic recording layer.

Problems to be Solved by the Invention However, although the unevenness of the magnetic recording layer, which is formed using fine particles as a nucleus, has a remarkable effect on improving practicality, it is also difficult to improve the recording wavelength by shortening the recording wavelength and widening the signal band. There is a problem in density recording that C/N cannot be ensured, and improvements have been desired.

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 excellent high-density recording characteristics.

Means for Solving the Problems In order to solve the above problems, the magnetic recording medium of the present invention has the following features:
An obliquely deposited film and a perpendicularly magnetized film are laminated on a polymer film having granular projections, and the vertical coercive force of the obliquely deposited film is made larger than that of the perpendicularly magnetized film.

Effect: The magnetic recording medium of the present invention has the above-described configuration, which improves the self-demagnetization of the obliquely deposited film in the short wavelength region, and in which the obliquely deposited film is arranged to improve the output in the long wavelength region in order to widen the band. Since the rate of deterioration of the characteristics of the perpendicularly magnetized film in the short wavelength region becomes almost negligible, a good C C can be obtained in a wide band.

Embodiments Hereinafter, embodiments of the present invention will be described 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 polyethylene terephthalate, polyethylene naphthalate, poly1 phenylene sulfide,
Polymer film 2 such as polyetheretherketone, polyamide, polyimide, etc. is Az203. CaO, Zn
O, TiO2, 5i02° Carbon, polyester sphere, etc. fine particle coating layer, 3 is Co, Co-Ni, Co-
Cr, Co-Ta, Co-8m.

Measure the coercive force in one plane and the coercive force in the vertical direction with obliquely deposited films such as Co-0, Co-Ni-0, Co-Ni-Cr, etc.
Focusing on the coercive force in the vertical direction, it is preferable to set it larger than the coercive force in the vertical direction of the perpendicularly magnetized film 4, preferably 20 inches or more. This perpendicular magnetization film 4 is made of Go-Or,
Co-Ti, Co-W, Co-Mo, Co-Cr-
These include a sputtering film of Nb, etc., and an electron beam evaporation film.

The vertical coercive force of the obliquely deposited film 3 can be controlled by mainly selecting the material conditions and the minimum incident angle, but it is of course possible to set the conditions by understanding the relationship with other parameters. It is. 6 is a protective lubricating layer, which is a thin carbide film, a thin oxide film, and a thin sulfide film.

Nitride thin film, plasma polymerized film, carbon film, fatty acid.

It is composed of one or more selected combinations from fatty acid esters, aliphatic alcohols or their alkoxides, polyhydric alcohols, sulfurized fatty acids, aliphatic mercaptans, modified silicone oils, perfluoropolyethers, and the like.

Examples of the present invention will be further described below in comparison with comparative examples.

[Example-1] On a polyethylene terephthalate film with a thickness of 10 μm, 120 T z O2 particles with a diameter of 18 pieces/(μm
), and CoCo-N1 (80% Co) was electron beam evaporated thereon along a cylindrical key ay7 with a diameter of 1fi,
1060 obliquely deposited films were formed.

The film was formed under conditions such that the oxygen partial pressure was 7.6X10 (Toττ), the minimum incident angle was 20 degrees, and the incident angle directly above the evaporation source was 6o degrees. 1
090 (Oe) film was formed, and Co-Cr (
Co:80.2wt%) as a target.

900 perpendicular magnetization films with a perpendicular coercive force of 870 (0.) at 13.56 (MHz) and 1.1 (KW) are arranged, and 78971 "Vonprin Z-26" manufactured by Montefluos is placed on top of them. It was coated and made into 8mm tape.

[Example-2] In Example-1, the in-plane coercive force was 1020 (Oe
) A film with a perpendicular coercive force of 1000 (Oe) is
Co-0r-Nb (Co:C
The same configuration was used except that 1000 perpendicularly magnetized films with a perpendicular coercive force of 800 (Os) were arranged at 13 and 56 (MHz) 1 (KW) with a target of r:Nb = 79:14 near wt%). I made a prototype of 8mm tape.

[Comparative example]

In Example-1, the Co-Ni-0 film had an in-plane coercive force of 1050
(Os) 100 under the condition of vertical coercive force 800 (Oe)
An 8 mm tape was prepared under the same conditions except that a Co-0r perpendicularly magnetized film was formed with a coercive force of 1000 (Oe) in the perpendicular direction and 1000 layers were formed. 8 pieces of the above tape
As a result of modifying the millivideo and comparing C in the 10 (MHz) band, if the comparative example is o (dB), then the example -
1 is +3.5 (dB), Example-2 is +a, 5 (dB)
Met.

Also, when the band is 13 (MHz), the C/N of the comparative example is +4.9 (dB) for Example-1, and +4.1 (dB) for Example-2, which is an even greater difference. Open, wideband C
The value of the example was obvious in improving /N.

Effects of the Invention As described above, according to the present invention, there is an excellent effect that a broadband C/N ratio can be realized with a structure in which the durability is improved by the granular protrusions.

[Brief explanation of the drawing]

The figure is an enlarged sectional view of a magnetic recording medium according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Polymer film, 2... Fine particle coating layer, 3... Oblique vapor deposition film, 4... Perpendicular magnetization film.

Claims (1)

[Claims] A magnetic recording medium characterized in that an obliquely deposited film and a perpendicularly magnetized film are laminated on a polymer film having granular protrusions, and the perpendicular coercive force of the obliquely deposited film is made larger than the vertically coercive force of the perpendicularly magnetized film. .