JPH01128221A - magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve the magnetic characteristics of the surface layer part of a perpendicularly magnetized Co-Cr film by providing an ion-implanted layer of a rare earth element to the surface layer part. CONSTITUTION:A fine particle coated layer 2 by fine particles of Eu2O3, etc., and the perpendicularly magnetized Co-Cr film 3 are laminated on a high- polymer film and the ion-implanted layer 4 formed by ion implantation of the rare earth element such as Pr is formed on the surface layer part of the film 3. A protective film 5 consisting of a thin hard carbon film, etc., and a lubricating agent layer 6 consisting of perfluoroalkylcarboxylic acid are successively formed on the layer 4. The oxygen of the part which is the cause for magnetical disturbance bonds to the rare earth element and the magnetic characteristics of the surface layer part become equal to the magnetic characteristics of the inside part if the implanted layer 4 is provided. The medium having excellent C/N is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording medium for perpendicular magnetic recording suitable for high-density magnetic recording.

Conventional technology Perpendicular magnetic recording is a technology for recording and reproducing by bringing a magnetic head into contact with a magnetic recording medium, and when the linear recording density exceeds 100 KBPI, its superiority over longitudinal recording becomes obvious, making it particularly suitable for digital recording. Because of this, it is thought to be a fundamental technology for future high-density storage, and research and development has been active in recent years. Perpendicular recording requires a magnetic recording medium with anisotropy different from that of conventional longitudinal recording, and currently, a Co-Cr perpendicularly magnetized film on a 2,...-7 polyiide film is used by sputtering, Although it may be manufactured using any electron beam evaporation method, it is known that materials with good crystal orientation and large perpendicular coercive force can provide relatively excellent high-density recording characteristics. [Refer to Applied Magnetics Section ``Perpendicular Magnetic Recording System'' (December 1960)].

On the other hand, improving durability is recognized as an important issue for practical use, and protective films and lubricants are being actively studied.
All of these causes spacing loss, which increases as the wavelength becomes shorter, and it has become important to find medium conditions with a large C/H without a protective layer.

Problems to be solved by the inventionHowever, polyimide and polyethylene terephthalate l/
-) in which a Co-Cr perpendicular magnetization film is continuously formed, C/H is being improved by degassing the film and improving the degree of vacuum in the background, but at present it is not sufficient. Since there is no known system that is sufficient and can bring durability and C/N close to practical levels, improvements have been desired.

The present invention has been made in view of the above-mentioned circumstances, and is intended to provide a magnetic recording medium with excellent durability and C/N ratio.

Means for Solving the Problems In order to solve the above-mentioned problems, the magnetic recording medium of the present invention has an ion-implanted layer of a rare earth element in the surface layer of a Co--Cr perpendicularly magnetized film.

Function The magnetic recording medium of the present invention has the above-described structure, so that the active rare earth element combines with oxygen to replace the oxide layer normally formed on the surface, which causes magnetic disturbances and causes noise. , the pure magnetic properties of Co--Cr appear, and since the same properties are exhibited internally, the C/N ratio is improved in the short wavelength range.

EXAMPLE Hereinafter, a magnetic recording medium according to 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 polyethylene terephthalate, polyethylene nitrate 1/-t, and polyphenylene sulfide.

In polymer films such as polyether sulfon, polyamideimide, polyimide, etc., 2 is Aj? zOs 1Eu20
A fine particle coating layer containing fine particles such as 3゜5i02, Tie, ZnO, polyester spheres, etc., and this layer may be composited with a polymer film in advance.

3 is a Co-Cr perpendicular magnetization film with Nb, Ru, and T as required.
a, Rh, etc. may be added, but high frequency sputtering method.

Formed by electron beam evaporation method etc. 6008 to 30
It is preferable that the perpendicular coercive force is in the range of 400 (Oe) to 1600 (Oe) with a film thickness in the range of 0.000 mm. 4 is Pr,
An ion-implanted layer of a rare earth element such as Sm has a sufficient effect as long as the implanted layer has a depth of at most about 50 mm and the implanted amount is equivalent to the amount of oxygen in the surface layer. 5 is a protective film such as a hard carbon thin plasma polymerized film or a MoS2 film, and 6 is a lubricant layer made of fatty acid, fatty acid amide, barfluoropholiether, perfluoroalkyl carboxylic acid, or the like. With the above configuration, p, C
The degree to which /N is improved is remarkable for short wavelength culms, and will be explained in more detail below in comparison with comparative examples. Thickness 12μ
diameter 12 m on polyethylene terephthalate film
1Q/(μm)2 of Eu203 fine particles to 0, 4
13.56 (MH
Co-Or (Cr:
A Co--Cr perpendicularly magnetized film was formed using a Co--Cr perpendicular magnetization film as a target. This Co-1Or perpendicular magnetization film consists of columnar fine particles with an average particle size of 370 particles and a height of 1400 mm, and the surface layer has 35 layers containing oxygen of 23 atoms. KeV Pr''- ions were implanted at 12 μA/-, and the oxygen in this layer, which made the magnetism of CO non-uniform, was replaced with an ion-implanted layer in which Pr atoms could be ignored. Ar 10 H2 == IX10-2 (Tor
r).

Using a discharge gas of Ar:H2=1:3, 13.5
6 (MHz).

A diamond-like hard carbon thin film with a thickness of 85 mm was deposited using a sputtering method using a high-frequency glow discharge of 1.22 (KW), and a lubricant layer of 56 perfluoroaracic acid was further deposited on top of it using a vacuum evaporation method. The magnetic tape had a width of 8mm and 6h. On the other hand, a comparative example is an 8 mm wide magnetic tape in which Pr ion implantation was not performed and other structural conditions were the same. A comparative evaluation was made using a modified 8mm video of both tapes. Using an amorphous alloy sputter laminated ring head with a gap length of 0.17 μm, a rectangular wave signal with a bit length of 0.25 μ”%) and a rank width of 7 μm was recorded, and the reproduction C/N was compared. On the other hand, the C/N of 2.1 (dB) was better.The wavelength was further shortened and the bit length of 0.15 μm was better in the example.
B) It showed good C/N. Even in the methyl state, the reproduction output was reduced by 2 (dB), but the durability was good, lasting more than 60 minutes.

Effects of the Invention As described above, the present invention has the excellent effect of providing a magnetic recording medium for perpendicular magnetic recording with good C/H at short wavelengths.

[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. 1... Polymer film, 2... Fine particle coating layer, 77, -7 3... Co-Cr perpendicular magnetization film, 4...
Rare earth ion implantation layer, 5...Hard carbon thin film, 6
......Lubricant layer. Name of agent: Patent attorney Toshio Nakao and 1 other person6-
Zukan skin publication layer

Claims (1)

[Claims] A magnetic recording medium characterized in that a rare earth element ion implantation layer is provided in the surface layer of a Co--Cr perpendicularly magnetized film.