JPS63127418A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a good S/N, error rate, etc., even in short wavelength recording by executing diagonal vapor deposition to provide underlying layers from both of the longitudinal direction of a high-polymer film on a fine particle coated layer on said film and depositing a thin ferromagnetic metallic film thereon. CONSTITUTION:The fine particle coated layer 8 consisting of fine particles 9 of carbon, etc., and a resin layer 10 of polyester, etc., is formed on the high- polymer film 7 consisting of PE terephthalate, etc. The underlying layers 11, 12 formed by the diagonal vapor deposition from both of the longitudinal direction are provided thereon. The thin ferromagnetic metallic film 13 consisting of Co-Ni, etc., and a protective layer 14 are laminated on said layers. As a result, the generation of voids by the shadowing which arises at the time of the diagonal vapor deposition of the ferromagnetic metal by the shape of the fine particles is hardly discovered and since the uniformity is thereby magnetically improved, the good characteristics such as S/N, error rate and peak shift are obtd. even in short wavelength recording and reproduction.

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 In recent years, there has been remarkable progress in increasing the density of magnetic recording.

There is a strong desire to put into practical use a ferromagnetic metal thin film type magnetic recording medium that does not have a non-magnetic part such as a binder in the magnetic recording layer. [For example, foreign journals: IEEEETRANSAC
TIONS ON MACiNETIC8Vol
-MAG-21, No-3, P, P, 1217-12
20 (1985)] The problem with magnetic recording media having such a structure is to improve the signal output-to-noise ratio (hereinafter referred to as S/N) and durability in a well-balanced manner. FIG. 2 is an enlarged sectional view of a conventional magnetic recording medium. In Figure 2, 1 is a polymer film such as polyethylene terephthalate film, 2 is a fine particle coating layer, and 5 is a polymer film such as a polyethylene terephthalate film.
Fine particles 3 such as iQ2 and carbon are fixed with polyester resin 4. 6 is a ferromagnetic metal thin film such as an obliquely deposited film or a perpendicular magnetization film, 6 is stearic acid, barfluoro V
ol, MAG 21, A 5, P, P,
1624-1526 (1986), U.S. Patent No. 4,5
No. 64,549.

JP-A-65-113898, JP-A-59-924
See Publication No. 28, etc.] A magnetic recording medium having such a structure has improved running properties, still characteristics, etc., and can be said to be a system close to practical use.

Problems to be Solved by the Invention However, in the above configuration, the recording wavelength is 0.8 μm.
Improvements are desired, such as the modulation noise becoming thicker, the error rate in digital recording being insufficient, and the peak shift becoming large as the length becomes too short. The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a durable magnetic recording medium with improved S/N, error rate, and peak shift.

Means for Solving the Problems In order to solve the above problems, the magnetic recording medium of the present invention comprises:
A fine particle coating layer is placed on a polymer film, and a ferromagnetic metal thin film is placed on top of the fine particle coating layer with an underlayer formed by diagonal vapor deposition from both directions in the longitudinal direction.

Effect: Due to the above-described structure, the magnetic recording medium of the present invention almost eliminates the generation of voids due to shadowing that occurs during oblique deposition of ferromagnetic metal due to the shape of fine particles, and therefore improves magnetic uniformity. , S/N, error rate, and peak shift are improved, and since the shape effect remains, durability does not deteriorate; on the contrary, since voids are eliminated, durability regarding storage is improved.

EMBODIMENT OF THE INVENTION Hereinafter, 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 7 in the figure represents polyethylene terephthalate, polyethylene phthalate, polycarbonate, cellulose diacetate, and polyether sulfone.

Polymer film made of polyamide, polyamide, polyamideimide, polyimide, etc. 8
is a fine particle coating layer, carbon, Ag2O3°Sio2.
CaCo3. It consists of fine particles 9 such as polyethylene spheres or polyester spheres, and a resin layer 1o of polyester, polycarbonate, polyurethane, epoxy, etc. to fix the fine particles 9.

11 is a base layer deposited obliquely from one direction in the longitudinal direction;
Preferably, it is discontinuous. The angle of incidence is 50 degrees or more,
More preferably, it is performed by electron beam evaporation at 65 degrees or more,
Constituent elements are Cr and Ni-Cr.

Mo, Ti, Ge, etc. are preferred. Reference numeral 12 denotes a base layer which is similarly deposited obliquely from the other longitudinal direction, and is preferably composed of the same types of constituent elements.

In order to eliminate voids in this underlayer, it is necessary to set some conditions, but if necessary, the ion blating method increases the mobility of the deposited atoms, so it is easy to set the conditions.

13 is Co-Ni, Co-Fe, Co-0, Co
-〇s, Co-P.

Co-Ti, Co-Cr, Co-Cu,
Co-Mo, Co-Mg.

Co-W, Co-Cr-Nb, Co-Ni-0,
A ferromagnetic metal thin film formed by a sputtering method, an electron beam evaporation method, etc. using Co--N1-P, etc., 14 is a fatty acid, a fatty acid amide, a metal soap, and a perfluorocarboxylic acid.

This is a protective layer consisting of a single layer or a laminated layer of a plasma polymerized film, an amorphous carbon film, or the like.

An example of a specific numerical comparison is shown below.

On a polyethylene terephthalate film with a thickness of 12 μm, 16 particles/(μ
m)2. A fine particle coating layer fixed with 30 pieces of polyester resin was placed along a cylindrical can with a diameter of 50 μm, and 2
Cr was electron beam evaporated while winding at 6 m/miR. The can temperature is 46℃, and the Cr is 1.4μm.
At a deposition rate of /sec and a minimum incident angle of 66 degrees, an amount equivalent to a thickness of 64 when deposited uniformly was deposited, and while being wound in the opposite direction along the cylindrical can, the same minimum incident angle was Cr was deposited at 66 degrees under the same conditions as above. On top of that, along a cylindrical can with a diameter of 1 m, at a minimum angle of incidence of 40 degrees.

Co-N1 (
Tape A was prepared by electron beam evaporation of 0.16 μm of 20 wt %). Tape B is Co-N
Instead of i, a perpendicular magnetization film of 0.17 μm was formed by high-frequency magnetron sputtering using a Co-Cr (20.5 wt% Cr) target.
Tapes C and D were prepared as comparative examples. Tape C is Co
Tape A has the same structure as Ni-based tape A without a Cr diagonally vapor-deposited base. Tape D has the same Co-Cr base (tape B) without a base. Tape A-
All D are 8 mm wide magnetic tapes on which perfluoroacetic acid was deposited by 55 people using a vacuum deposition method.

Tapes A to D were compared and examined using a modified 8mm video tape recorder. The head has a gap length of o, 14 μm.
Using a ferrite head, the center frequency was shifted to record at a recording wavelength of 0.6 pm, and the reproduction S/N was compared. The initial S/N ratio was compared with tape A as o (dB), and as a result, tape B was +1.2 (dB) and tape C was -
2,2 (dB), Tape D is -1,0 (dB) Te, 4
137 when regenerating 137 times at 0'CB5%RH
The S/N for the second playback is tapes A, B, C, and D.
, 3 (dB), +1.0 (dB).

-3.9 (dB), -2.9 (dB).

The amount of peak shift when recording and reproducing a rectangular wave signal with a pit length of 0.22 μm is for tapes A, B, and C.

D is 0.01pm or less, 0.04prn, 0, respectively.
．． It was 03 μm. Also, the error rate is for tapes A, B,
C.

D respectively, 7.6 Xl 0-6.6.9X 1 o-
It was 6,3,9X10-5゜2.2X10''''5.

In addition, after being left at 60 °C and 90% RH for 18 days (7) 'j
-5-rate is 9X10-6.7.2X10-6゜8.
7X10. 5. It was 1×10.

Effect of the invention As described above, according to the present invention, S/N, error rate.

The properties such as peak shift are good even in short wavelength recording and reproduction, and the dust resistance and durability are also good, and there is an excellent effect that a highly reliable high-density magnetic recording medium can be obtained.

[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. 7... Polymer film, 8... Fine particle coating layer, 11.12... Oblique vapor deposition base layer, 13
...Ferromagnetic metal thin film.

Claims (1)

[Claims] A fine particle coating layer is arranged on a polymer film, and a ferromagnetic metal thin film is arranged on top of which a base layer is formed by diagonally vapor-depositing from both directions in the longitudinal direction. magnetic recording medium.