JPH0677302B2 - Magnetic recording medium - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called metal thin film type magnetic recording medium in which a magnetic recording layer made of a ferromagnetic metal is arranged on a polymer film on the magnetic recording medium.

2. Description of the Related Art Conventionally, what has been widely put to practical use as a magnetic recording layer is γ-Fe ₂ O ₃ , CrO ₂ doped with γ-Fe ₂ O ₃ , Co, or a ferromagnetic metal such as iron or an alloy microparticle. This is a coating type magnetic layer in which a powder magnetic material is dispersed in an organic binder such as a vinyl chloride / vinyl acetate copolymer, a styrene butadiene copolymer and an epoxy resin, coated on a substrate such as a polymer film and dried. With the increasing demand for high-density recording in recent years, the so-called metal thin-film magnetic recording using a ferromagnetic metal thin film as a magnetic recording layer, which is expected to give an excellent signal-to-noise ratio (S / N) in the high-density region. The medium is drawing attention, and efforts are being made toward its practical application.

[For example, Foreign Transactions: IEEE Transaction on Magnetics, MAG-10, No2, P]
P.368-373 (1974)] The problem of such a magnetic recording medium lies in how to achieve a high level of balance between electromagnetic conversion characteristics and practical durability, and various proposals have been made.

FIG. 3 is an enlarged sectional view of a conventional magnetic recording medium.

In FIG. 3, reference numeral 1 is a polymer film 2, a magnetic recording layer 3 made of a ferromagnetic metal thin film, and a protective film. The protective film of No. 3 has partially succeeded in preventing scratches generated on the magnetic recording layer during high-speed sliding contact with the magnetic head and improving runnability. [For example, JP-A-52-153707, JP-A-53-88704, JP-A-59-171026] Further, as the polymer film 1, JP-A-59-84928 and JP-A-59- It is possible to further improve the scratch resistance and the running property by providing many irregularities on the surface of the magnetic recording layer to reduce the vacuum contact area with the magnetic head by using the one disclosed in Japanese Patent No. 121631. It is also known to be possible.

It is also known that a Co alloy thin film containing oxygen as a magnetic recording layer is excellent in still durability and S / N.
[Foreign papers: IE Magnetics Society (IEEE Tra
nsaction on Magnetics) Vol MAG-20, PP.824-826 (19
84)] Problems to be Solved by the Invention However, in the configuration described above, when the signal density becomes 6 × 10 ⁻⁸ cm ² or more due to high density, S / N and practical durability There is a problem in that the balance with head wear becomes insufficient.

Means for Solving the Problems In order to solve the above problems, the magnetic recording medium of the present invention has a ferromagnetic metal thin film containing oxygen on a polymer film, on which a fine particle coating layer, and a strong enzyme containing enzyme. It has a structure in which a magnetic metal thin film is arranged.

Operation The present invention has the above-described configuration, in the ferromagnetic metal thin film containing oxygen, compared to the case where the projections formed by the fine particles are formed at one time with the film thickness of the magnetic recording layer necessary for obtaining the saturated output. It is thought that this is because the formation of coarse protrusions due to uniform and abnormal crystal growth disappears, and that destruction of the thin film on the fine particle coating layer due to external force is less likely to occur as the thickness of the thin film is smaller because the internal stress is less accumulated. From the above, the magnetic recording layer is extremely less likely to wear the magnetic head with the abrasion powder, and the S / N is also improved because the constituent particles of the ferromagnetic metal thin film containing oxygen are finely divided, Both are well balanced.

Examples Hereinafter, examples of the present invention will be described with reference to the drawings. 1 and 2 are enlarged sectional views of a magnetic recording medium according to an embodiment of the present invention.

In FIG. 1, 4 is a polymer film made of polyethylene terephthalate film having a thickness of 10 μm and 5 is Co-Ni-O.
The film is 70:18:12 in atomic% ratio and the thickness is 0.1 μm. The ferromagnetic metal thin film used in the examples including this thin film was formed by a winding type vacuum vapor deposition machine including a cylindrical can having a diameter of 1 m and an electron beam evaporation source. The magnetic characteristics were adjusted by the minimum incident angle, oxygen partial pressure, vapor deposition rate, and the like.

6 is a fine particle coating layer, which comprises fine particles 7 and a resin layer 8 for fixing the fine particles.
The particles were 0Å silica particles, and the resin was polyarylate. The density of the silica fine particles was 100 / (μm) ² and the thickness of the polyarylate resin was 50Å on average.

A Co-Ni-O film 9 was vapor-deposited on this. Atomic% ratio 66:16:18
The film has a thickness of 0.05 μm.

As a comparative tape, a fine particle coating layer 6 having the same specifications is placed on a polymer film 4, and a Co—Ni—O film of 0.15 μm is formed thereon.
What was arranged m was used. The magnetic properties were the same and compared. Therefore, the atomic% ratio of the Co-Ni-O film was 68:17:15. The coercive force was 1050 (Oe) and the squareness ratio was 0.76.

About 40 Å of stearic acid was vapor-deposited on the surface of each of the tapes of Examples and Comparative Examples by a vacuum vapor deposition method and evaluated.

The table shows the comparison of S / A by the usage time of the magnetic head. S / N is a relative comparison at a memory wavelength of 0.75 μm and a track pitch of 14 μm. The environmental conditions are 30 ℃ and 80% RH.

As described above, according to this example, it is understood that a good S / N can be secured for a long time by dividing the ferromagnetic metal thin film containing oxygen and interposing the fine particle coating layer therebetween.

FIG. 2 is an enlarged sectional view of another embodiment of the present invention.

In FIG. 2, 10 is a polymer film made of a polyethylene 2-6 naphthalate film having a thickness of 6.5 μm, 11 is a discontinuous film mainly composed of a water-soluble polymer adhered to the polymer film, and is an average of methylcellulose. A roughness of 100Å was used. 12 is a ferromagnetic metal thin film containing oxygen. Co-O film 0.09
The atomic% ratio of μm and Co—O was 86:14. A fine particle coating layer 13 is composed of Fe ₃ O ₄ fine particles (diameter 160 Å) 14 and a resin epoxy resin layer (average thickness 30 Å) 15 for the solid chamber. 16
Is a ferromagnetic metal thin film containing oxygen and is a 0.09 μm Co-O film (C
o: O = 83: 17), and a stearic acid vapor-deposited film as a lubricant is about 45
Å Distribute and tape.

In the comparative tape, Fe ₃ O ₄ fine particles were directly applied on the discontinuous film at the same density [about 60 pieces / (μm) ² ] and Co-O was applied on top of it.
[Co: O = 84:16, magnetic characteristics are coercive force 1100 (Oe), squareness ratio
The value was adjusted to 0.81 in the same manner as the actual example. A film having a thickness of 0.18 μm and a stearic acid vapor-deposited film of about 45 Å was also used.

With environmental conditions of 25 ° C and 75% RH, two types of alloy heads were used, and the recording wavelength was 0.66 μm and the track pitch was 10 μm.
The relative reproduction S / N was compared.

As described above, according to the present embodiment, the ferromagnetic metal thin film containing oxygen, the fine particle coating layer, and the ferromagnetic metal thin film containing oxygen are arranged on the water-soluble polymer discontinuous film adhered on the polymer film. Thus, it is understood that a good S / N can be obtained for a long time by high density magnetic recording / reproducing using an alloy head.

In the two examples, the polymer film may be polyimide, polyamide, polysulfone, polycarbonate, polyphenylene sulfide, polyparavanic acid, or the like.

The fine particles may be TiO ₂ , CaCO ₃ , BaSO ₄ , polyester spheres, etc., and the resin for fixing the fine particles may be polyester, polyamide, polyimide, polystyrene, polycarbonate, polyacrylate, silicone, urethane, phenol, etc. .

The discontinuous film mainly composed of the water-soluble polymer adhered to the polymer film may be polyvinyl alcohol, gum arabic, casein, gelatin, carboxymethyl cellulose or the like.

Other ferromagnetic metal thin films containing oxygen include Co-Fe-O and Co-Cr-
O, Co-Ti-C, Co-Si-O, Co-Mg-O, Co-W-O, Co-Mo-
It may be O, Co-Cu-O, Co-Sb-O, Co-Sm-O or the like.

As described above, according to the present invention, high density magnetic recording / reproducing
It has an excellent effect that S / N can be maintained in good condition for a long time.

[Brief description of drawings]

1 and 2 are enlarged sectional views of a magnetic recording medium according to an embodiment of the present invention, and FIG. 3 is an enlarged sectional view of a conventional magnetic recording medium. 4,10 …… Polymer film, 5, 9, 12, 16 …… Oxygen containing ferromagnetic metal thin film, 6, 13 …… Fine particle coating layer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigeki Kawase 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor ▲ Hide ▼ Hideki Ta, 1006 Kadoma, Kadoma City, Osaka Prefecture, Matsushita Electric Industrial Co., Ltd. (56) References JP 59-207422 (JP, A) JP 59-223934 (JP, A) )

Claims (1)

[Claims] 1. A magnetic recording medium comprising a polymer film, a ferromagnetic metal thin film containing oxygen, a fine particle coating layer, and a ferromagnetic metal thin film containing an enzyme.