JPH05128471A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To attain drastically high reliability by solving generation of head touch change by dimensional change or dimensional change of a recording part even in an environment severe in humidity change in a magnetic recording medium in which a ferromagnetic metallic thin film is a magnetic recording layer. CONSTITUTION:A fluorine contained hard carbon films 3, 8 are provided on both side of a high polymer film 1 and at least on one side of the surface, a lubricating layer 4 and furthermore the ferromagnetic metallic thin film 5 are provided. The magnetic recording medium constituted by this way drastically increases hygroscopic resistance and dimensional change to humidity change is lowered, excellent head touch is attained and drastically high reliability is attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium having a magnetic recording layer of a ferromagnetic metal thin film suitable for high density magnetic recording such as perpendicular magnetic recording.

[0002]

2. Description of the Related Art In the field of magnetic recording, miniaturization,
With improvements in performance such as longer time and digitalization, the track density and linear recording density have improved remarkably.
The miniaturization of recording / reproducing devices is also being promoted, and in the future, the focus will be on how many recording areas can be secured in a predetermined cassette space, and thinning of the recording medium is being considered. Among them, a magnetic tape using a ferromagnetic metal thin film as a magnetic recording layer is promising for improving the recording density in terms of track density and linear recording density, and is advantageous for thinning the magnetic recording layer. One having a recording layer (JP-A-59-175032), one having a ferromagnetic metal thin film on one side of a polymer film, and a soft magnetic thin film on the other side (JP-A-60-50717), Many proposals have been made such as one in which an in-plane magnetized film is arranged on one side of the molecular film and a perpendicular magnetized film is arranged on the other side (JP-A-60-11332).

[0003]

However, the thin film having the above-mentioned constitution by disposing the thin film on both sides of the polymer film is used in an environment where the humidity changes greatly, so that the entire track is Since there is a problem that a good head touch cannot be obtained and the RCM error rate, skew, etc. are deteriorated, improvement is desired.

The present invention has been made in view of the above circumstances, and provides a magnetic recording medium capable of obtaining a good head touch even in an environment where humidity changes are severe.

[0005]

In order to solve the above-mentioned problems, the magnetic recording medium of the present invention has a fluorine-containing hard carbon film on both sides of a polymer film, a lubricating layer on at least one side, and a strong layer. A magnetic metal thin film is arranged.

[0006]

The magnetic recording medium of the present invention has the above-mentioned structure.
The highly water-repellent lubricating layer adheres to the magnetic layer, and the fluorine-containing hard carbon film, which has the property of strongly repelling water, adheres to the polymer film surface, resulting in a synergistic effect of the lubricating layer and the fluorine-containing hard carbon film. Since the moisture absorption resistance is greatly increased, the dimensional change and the curl change are small with respect to the humidity change, and the problems such as the head touch change of the magnetic tape and the magnetic disk and the dimensional change of the recording portion are eliminated.

[0007]

The magnetic recording medium of the present invention will be described in detail below with reference to the drawings. The drawing is an enlarged view of a magnetic recording medium according to an embodiment of the present invention.

In FIG. 1, 1 is polyethylene terephthalate,
Polymer film such as polyethylene naphthalate, polyimide, polypropylene, thickness less than 10μm, 4μm
Are used up to. 2 is an undercoat layer on the magnetic surface side, which is Si
_{O 2, Al 2 O 3,} CaCO 3 or the like particulate or worm-like elevations layer and, particles and suitably selected from a combination of worm-like elevations layer such, S / N characteristics and running durability and the point of still durability, etc. Therefore, the maximum roughness of 20 mm is desirable when a short wavelength is targeted. Numeral 3 is a fluorine-containing hard carbon film on the magnetic surface side, which is a sputtering method using graphite as a target, or a plasma CV using a mixed discharge gas of methane, propane, etc. and fluorine gas.
Formed by method D, the amount of fluorine is 10% carbonized
As described above, preferably 20% or more and the film thickness is 20 mm or more, preferably 50 mm or more, in order to minimize the dimensional change. Reference numeral 4 denotes a lubricating layer, which preferably has a polar group such as fatty acid, carboxylic acid, higher alcohol, and sulfonic acid, and a film thickness of 2 mm or more, preferably 4 mm or more has a large water repellent effect.

Reference numeral 5 is a ferromagnetic metal thin film, Co, Co--N
i, Co-O, Co-Cr, Co-Ni-O, Co-T
i, Co-Cr-O, Co-W, or the like, which is formed by a sputtering method, an electron beam evaporation method, or the like, and may have a multilayer structure if necessary, or may be formed via a soft magnetic layer or the like. Needless to say, it may be a double-sided access type in which the other side is similarly arranged. Reference numeral 6 is a protective lubricant layer, which is a protective film such as a plasma polymerized film, a carbon film, or a TiC film, on which a lubricant such as fatty acid ester, higher alcohol, or perfluoropolyether is arranged to reduce spacing loss and ensure durability. Therefore, the film thickness and the combination of materials may be determined by experiments in good balance, and there is no particular limitation.
Reference numeral 7 denotes a running surface side undercoat layer for imparting a shape, which may be formed basically in the same way as in 2, but the roughness can be increased. Numeral 8 is a fluorine-containing hard carbon film on the running surface side, which may be formed basically according to the same concept as in 3, and the film thickness is constituted by a film thickness necessary to secure the total thickness of the tape or disk. desirable.

Hereinafter, the examples of the present invention will be described more specifically in comparison with comparative examples.

[0011] (Example 1) polyethylene terephthalate having a thickness of 7μm phthalate film of SiO ₂ particles having a diameter of 12 nm 20 months / [mu] m ² placed on, a diameter of 180nm on the other side CaCO ₃ particles 0.5 months / [mu] m ² Ar + CF ₂ + H ₂ = 0.
1 Torr, Ar: CF ₂ : H ₂ = 1: 1: 5, 100 kHz,
Sputtering is performed under the sputtering condition of 1000 W,
Fluorine-containing 20% fluorinated hard carbon film of 80 nm on the SiO ₂ fine particle side, fluorine-containing 20% fluorinated 20% on the CaCO ₃ fine particle side, 2
A fluorine-containing hard carbon film having a thickness of 00 nm is arranged, and a lubricating layer having a thickness of 6 nm is further formed on the SiO ₂ fine particle side by a solution coating method, and CO is formed thereon along a cylindrical can having a diameter of 50 cm to form 5 × 10. Electron beam vapor deposition was performed in oxygen of ^-5 Torr at a minimum incident angle of 30 degrees to form a 0.15 μm Co-O film, and a plasma polymerized film using pentacarbonyl nickel as a monomer gas was further applied to 0.1 Torr. , 100kHz, 800
A 10-nm tape was formed under the condition of W, a perfluoropolyether was formed thereon as a lubrication layer by a solution-coating method to a thickness of 4 nm, and the tape was cut into a width of 8 mm to manufacture an 8 mm tape as a prototype.

(Example 2) An 8 mm tape was produced by placing each element on a polyethylene terephthalate film having a thickness of 6.3 μm under the same conditions as in Example 1.

(Comparative Example 1) On a polyethylene terephthalate film having a thickness of 7 μm, 20 particles / μm ² of SiO ₂ fine particles having a diameter of 12 nm were arranged, and Co was deposited thereon in the same manner as in Example 1.
-O film is placed 0.15 μm, plasma polymerized film and lubricant layer are placed in the same manner, and CaC of 180 nm in diameter is placed on the opposite side of the film.
0.5 mm / μm ^{2 of} O ₃ fine particles were arranged, and a TiC film was arranged thereon to a thickness of 150 nm to make an 8 mm tape.

(Comparative Example 2) In Comparative Example 1, the film thickness was 6.
An 8 mm tape, which was replaced with a 3 μm polyethylene terephthalate film, was manufactured as a prototype.

A commercially available 8 mm video (SO
Comparative evaluation was carried out by EV-S900 manufactured by NY. PCM error rate (LP mode) especially affected by head touch
The results evaluated in Table 1 are shown in (Table 1). Record 23 ° C 65
After performing in% RH, leave it in each environment for 1 week
M error measurement was performed at 23 ° C. and 65% RH. The results are shown in (Table 1).

[0016]

[Table 1]

As is clear from this (Table 1), in Examples 1 and 2, even after being left in their respective environments, compared with the Comparative Example, PC
The M error rate was improved by one digit or more, and good head touch was confirmed.

[0018]

As described above, according to the present invention, by providing the fluorine-containing hard carbon film and the lubricating layer on both sides of the polymer film, a good head touch with a small dimensional change and curl change due to being left in a high humidity environment can be obtained. It is possible to obtain an excellent thin magnetic recording medium with the effect of being obtained.

[Brief description of drawings]

FIG. 1 is an enlarged view of a magnetic recording medium according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polymer film 2 Magnetic surface side undercoat layer 3 Magnetic surface side fluorine-containing hard carbon film 4 Lubricating layer 5 Ferromagnetic metal thin film 6 Protective lubricant layer 7 Running surface side undercoat layer 8 Running surface side fluorine-containing hard carbon film

Claims (1)

[Claims] 1. A polymer film having fluorine-containing hard carbon films on both sides, and a lubricating layer on at least one surface, and
A magnetic recording medium having a ferromagnetic metal thin film formed thereon.