JPS63127419A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve both of S/N and durability by depositing a sputtered magnetic layer of the same alloy on a 1st magnetic layer formed by diagonal vapor deposition of a ferromagnetic alloy on a high-polymer film and providing an oxide layer thereon. CONSTITUTION:The 1st magnetic layer 7 is formed by diagonal vapor deposition of the ferromagnetic alloy such as Co-Ni on the high-polymer film 5. The sputtered magnetic layer 8 is deposited of the same ferromagnetic alloy by a sputtering method on said layer and the oxide layer 10 and a protective lubricating layer 11 are laminated thereon. Since this medium has the oxide layer 10 on the surface of the sputtered magnetic layer 8, the durability is obtd. even if the content of the oxygen of the magnetic layer 7 formed by the diagonal vapor deposition is lowered. The decrease in the saturation magnetic flux density is thus averted. Since the activity of the sputtered metal element is high, the degrees of coating and adhesion are increased and both of the durability and S/N are improved.

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.

BACKGROUND OF THE INVENTION In recent years, there has been remarkable progress in increasing the density of magnetic recording, and the practical application of magnetic recording media with ferromagnetic metal thin films as magnetic recording layers is expected, and development is progressing in various fields [for example,
See Japanese Patent Publication No. 23208, Japanese Patent Publication No. 41-19389, Japanese Patent Publication No. 58-91, etc.). The problem with such magnetic recording media is to ensure the signal output-to-noise (S/N) ratio and durability.
As disclosed in the publication, a ferromagnetic metal thin film that will become a magnetic recording layer is formed on a polymer film directly or via an underlayer by a method of oblique vapor deposition with a trace amount of oxygen interposed,
A film with a protective film and a lubricant layer is close to practical, and a perpendicularly magnetized film requires 20 W of Cr obtained by sputtering.
The development of Co-Cr alloy films including around t% is the most advanced [see Japanese Patent Laid-Open Nos. 61-77126 to 77128, etc. Fig. 2 shows an example of a conventional magnetic recording medium; Polymer film such as polyethylene terephthalate film, 2 is a fine particle coating layer in which fine particles such as carbon or A42O3 are dispersed and fixed with resin, and 3 is Co-N1 (e.g. Ni) while introducing oxygen along the cylindrical can. 4 is a lubricating film made of stearic acid or the like.

In the magnetic disk having such a configuration, alloy ferromagnetic particles mainly composed of Fe particles were fixed with a resin at a recording wavelength of 0.75 μm. Compared to so-called alloy powder type tapes, it has an advantage of about 5 (dB) in output and 3 (dB) in S, and from the viewpoint of high-density recording characteristics, it will play a central role in improving magnetic recording in the future. Currently, efforts are being made in various fields to improve durability.The use of oxide films is considered effective for improving durability, and the above-mentioned The following methods are being considered: vapor deposition in such oxygen, surface oxidation using plasma oxidation in a post-Q process, or sputtering formation of an oxide.

Problems to be Solved by the Invention However, plasma oxidation of an obliquely deposited film,
The protective effect of sputtering oxide film is not sufficient, and if the durability is improved by adjusting the amount of oxygen intervening during oblique deposition, the saturation magnetic flux density decreases, and the electromagnetic conversion characteristics
In particular, improvements have been desired since the S/N ratio is decreasing.

The present invention was made in view of the above circumstances, and the S/N,
! : To provide a magnetic recording medium that is a well-balanced improvement of IT Kusumi.

Means for Solving the Problems In order to solve the above-mentioned problems, the magnetic recording medium of the present invention uses a first film in which a ferromagnetic alloy is obliquely deposited on a polymer film.
A sputtered magnetic layer formed by sputtering the same ferromagnetic alloy is disposed on the magnetic layer, and the surface of the sputtered magnetic layer has an oxide layer.

Function: The magnetic recording medium of the present invention has the above-described structure, so that durability can be obtained even if the amount of oxygen contained in the obliquely deposited magnetic layer is reduced, so that it can be constructed without significantly reducing the saturation magnetic flux density. Become. In addition, since the mobility of the sputtered metal element on the surface of the columnar fine particles constituting the obliquely deposited layer is large, the degree of destruction is large, and the adhesion strength is large.
Since the sputtered magnetic layer itself has a surface oxidation layer, it has good durability, and both S/N ratio and durability can be satisfied.

EXAMPLES Below, a magnetic recording medium according to an embodiment 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, and 5 in the figure is made of polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyphenylene sulfide, polyether sulfone, polyamide with a thickness of 3 μm to 15 μm. , polyamide-imide, polyimide, etc., 6 is an undercoat layer having a surface shape of earthworm-like elevations, 9 granular protrusions, singly or in combination, 7 is Co
-Ni.

Co-Fe, Co-5m, Co-Ta
, Co-Cr, Co-Mo.

Co-Pr, Co-B, Co-W, Co-Ti, C
o-5t, Co-〇.

Co-Os, Co-Y, Co-La,
A first magnetic layer obtained by oblique vapor deposition of Co-Ni-0, Co-Cr-Nb shade, 8 is a sputtered magnetic layer,
A sputtered film 9 made of the same alloy element as the first magnetic layer 7 is disposed on the first magnetic layer 7, and 1° schematically shows an oxidized layer of the sputtered magnetic layer.

The transition from the alloy to the oxide layer is not constructed as a separate layer, but is carried out by adjusting the manufacturing conditions to obtain the configuration. Reference numeral 11 denotes a protective lubricant layer, which may be made of fatty acids, fatty acid esters, fluorine compounds, etc. alone or laminated with a protective film such as an amorphous carbon film, but since the spacing loss increases as the wavelength becomes shorter, the overall The protective lubricant layer should be thick enough to last up to 100 people and remain effective.

Next, the results of mutual comparison between an example of the embodiment of the present invention and a comparative example will be explained.

On a polyethylene terephthalate film with a thickness of 10 μm, an undercoat layer containing Al12O3 fine particles with a diameter of 120 mm fixed on an average of 10 particles/μm1 using polyester resin (the resin thickness was set to be a 50-piece conversion amount) was placed. along a cylindrical can with a diameter of 1 m, the minimum angle of incidence is 46
Co-N 1 (Ni 20 wt %) was electron beam evaporated at a temperature of 100 nm. At that time, the amount of oxygen introduced was 0.117mlyr
The film thickness was 0.15μ. Besides, KCo-Ni
o, 06 by high frequency sputtering method targeting
A μmCo-Ni film was formed. At that time, two gas introduction nozzles were provided, one for introducing hydrogen gas and the other for introducing oxygen gas, so that an oxide layer was formed on the surface side. On top of this, 60 people vacuum-deposited perfluorobenic acid and made it into an 8mm wide magnetic tape. In the comparative example, Co
-N1 (Ni 20 wt%) was electron beam evaporated. At that time, the amount of oxygen introduced is o, sslym= and the film thickness is 0.
．． 19 μm.

It is an 8 mm wide magnetic tape on which Par 70 Robehhenic acid was deposited by 50 people.

The luminance signal S/N of the 8mm video tape recorder was 2.2 in the example compared to the comparative example. a (dB) is good.

The initial PCM error rate was 2 × 10 and 3 × 10, which was more than 10 times higher in the comparative example than in the example, and at 55°C and 90% RH.
The PCM error rate of the example after being left unused for two months was 4.5.
Although there is a change from X10 to 7.3X10, the comparison example has 5x10 to 9X10'''C legs, and the difference between the two is still maintained at nearly 10 times.

Effects of the Invention As described above, the present invention has the excellent effect of improving both the S/N ratio and durability of a magnetic recording medium in which a ferromagnetic metal thin film is used for magnetic recording.

[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... First magnetic layer, 8... Sputtered magnetic layer, 10...
・Oxide layer.

Claims (1)

[Claims] A sputtered magnetic layer formed by sputtering the same ferromagnetic alloy is disposed on a first magnetic layer formed by diagonally depositing a ferromagnetic alloy on a polymer film, and the surface of the sputtered magnetic layer has an oxide layer. magnetic recording media.