JPS60261016A - Magnetic recording medium - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

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

Conventional structure and its problems In recent years, advances in increasing the density of magnetic recording have been made by narrowing the track and at the same time shortening the recording wavelength. As loss becomes a significant influence, surface roughness is restricted and needs to be less than 500 octane at most, and in order to reduce loss at short wavelengths, the magnetic recording layer of magnetic recording media must be made thinner. Since it has become essential to use ferromagnetic silica metal, the development of such media has progressed in various fields.

Among them, the current amount of ft-C tape with consistent performance as a magnetic tape is obtained by oblique evaporation method.
The magnetic recording layer is an o-based partial oxide film, but it is not necessarily compatible with alloy heads, which are a prerequisite for increasing density. When recording and reproducing with a head or an amorphous alloy head, a stable reproduction output may not be obtained as with recording and reproducing with a ferrite head, and an improvement has been desired.

OBJECTS OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide a magnetic recording medium that can obtain stable reproduction output in a high-density region.

Structure of the Invention The magnetic recording medium of the present invention is characterized in that the magnetic recording layer is a partially oxidized film, and Cr is unevenly distributed on the surface, and the reproduction output in a high density region is stable.

DESCRIPTION OF THE EMBODIMENTS The present invention will be described below with reference to the drawings.
FIG. 2 is a partially enlarged cross-sectional view of the magnetic recording medium of the present invention, and is a diagram showing the main part of a vapor deposition apparatus used to obtain the magnetic recording medium of the present invention.

In FIG. 1, 1 is a polymer substrate, 2 is a worm-like raised layer, and 3 is a ferromagnetic thin film constituting a magnetic recording layer, which includes partially oxidized microcrystals 4 and Cr-segregated microcrystals 5.

In Fig. 2, 6 is a cylindrical can, 9 is a substrate, 8 is a delivery shaft, 9 is a winding shaft, 10 is an evaporation source container, 11 is a vapor deposition material, and 12 is for Cr supply. ion source, 13 is a mask, 14
is a steam flow schematically shown from an incident angle of 900 to θmip.

The polymer substrate that can be used in the present invention is polyester such as polyethylene terephthalate.

Polyolefins such as polypropylene, cellulose derivatives such as cellulose triacetate, polyamideimide,
Also included are polyamides, polyethersulfones, polybalaponic acids, polyimides, etc., which have a worm-shaped coating layer placed on one or both sides in advance.

Magnetic recording layers that can be used in the present invention include Co, C
o-Ni, Co-Fe, Co-B, Go-Cu
, Go-Cd.

Co-0r, Co-F, Co-Ge, C
o-Hf, Go-La, C.

-Mn, Co-Mo, Co-Mg, Co
-P, Co-Ru, Co-Rh, Co-
3n, Go-3i, Go-5m, Co-Ta
, Co -T i , Co -V , Co-W, Co
-Zn, Co-Ni-Fe, C.

-N i -P, Co -N 1-Mg, etc., some of which require a high concentration of Cr, as schematically shown in Figure 1. It is something to do. It is necessary that the high concentration portion of Cr be uniform in appearance on the scale of the recording wavelength and recording trunk width, but microscopically non-uniform.

That is, as will be described later, in order to always obtain the expected effect of being resistant to environmental changes and maintaining a certain level of abrasiveness, the high Cr concentration area must probably be reduced to 1/2% in proportion when viewed from the top. It seems that it is sufficient if it occupies 1/10 QoO from 100.

This means that, conversely, all of the high concentration areas of CI, e.g.
A medium obtained by implanting Cr into the entire surface by ion implantation etc. wears out the magnetic head at an excessively high rate, which actually impedes practical use.One method for obtaining such a medium is The apparatus shown in Figure 2 is used.

As shown in FIG.
Experimentally find the conditions under which a good medium can be obtained by injecting chromium ions and evaporating the furanium ions from step 2, and increasing the substrate temperature to increase the surface mobility of chromium. Good.

It is presumed that the effects of the present invention are due to a combination of the microscopic difference in hardness of the magnetic tape surface and the sharpness of the abrasive action of chromium, especially in its oxidized state. The effect is particularly remarkable in that even if the magnetic tape undergoes corrosion to a degree that cannot be recognized by changes in the amount of magnetic flux, it does not cause a reduction in reproduction output.

An example will be described in more detail below.

(Example) In Fig. 2, an electron beam evaporation source is arranged 26 crn directly below a cylindrical can (diameter 60 cm), and the optical axis is inclined at 46 degrees from the normal to the evaporation surface. A scanning deco-plasmatron type chromium ion source having a chromium ion source of the scanning type was arranged, and the mask was centered at a position where θ was 44 degrees.

207 rL/mm of polyimide film with a thickness of 15 μm
CoCo-N1 (20% Ni) was electron beam evaporated to 0.1 μm in oxygen at I×10 −6 Torr.

At the same time, a 10 mA Cr+ beam was applied to the center of the evaporation surface, and the OCr+ beam, in which Cr was evaporated, was pulse-scanned and adjusted so that it was randomly distributed on the magnetic tape surface.

The substrate temperature was controlled in the range of 160'C to 240°C.

Record a wavelength of 0.6 μm on the obtained 8-wavelength magnetic tape, store it in each environment, and then use the lowest value of replay output when playing back as the initial value for each tape and head system. o
[Relatively compared as dBl.

The area ratio of the high Cr concentration area was determined by X-ray analysis to be 1% of the entire surface.
It is expressed as a ratio.

The tape conditions and results are summarized in the table, but the comparison tape used was not irradiated with Cr+ ions.
The length of the tape measured was 80 m per roll, and under each condition 5
I tested each volume and selected the one with the worst results as a representative.

As is clear from the margin table below, the product of the present invention has extremely stable short wavelength reproduction output compared to conventional products. Equivalent stability was confirmed.

Of course, there was no relation to the direction of the axis of easy magnetization, and the same result was confirmed with other thin film heads and single-pole heads other than ring-type heads.

Effects of the Invention The magnetic recording medium of the present invention has a partially fermented film of ferromagnetic metal in which a high concentration portion of Cr is unevenly distributed as a magnetic recording layer.
It can stably reproduce short wavelength output regardless of the magnetic head, and its practical effects are significant.

[Brief explanation of the drawing]

FIG. 1 is a partially enlarged sectional view of the magnetic recording medium of the present invention, and FIG. 2 is a diagram showing the main part of a vapor deposition apparatus used to obtain the magnetic recording medium of the present invention. 1...Polymer substrate, 4...Partially oxidized microcrystal, 6...Or high concentration microcrystal. Name of agent: Patent attorney Toshio Nakao, 1st person, 2nd person
figure

Claims (1)

[Claims] 1. A magnetic recording medium comprising a partial oxide film as a magnetic recording layer, the element distribution on the surface being non-uniform, and Cr being unevenly distributed.