JP2583956B2 - Magnetic recording media - Google Patents

Description

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

2. Description of the Related Art In recent years, recording media have made remarkable progress, and magnetic recording media using a ferromagnetic metal thin film as a magnetic recording layer are being put to practical use.

FIG. 2 is an enlarged cross-sectional view of an example of a magnetic recording medium having a conventionally proposed ferromagnetic metal thin film as a magnetic recording layer. In FIG. 1, reference numeral 1 denotes a polymer film such as polyethylene terephthalate, polyphenylene sulfide, or polyether ether ketone, which may be provided with a fine particle coating layer, an undercoat layer, and the like as necessary.

Reference numeral 2 denotes a ferromagnetic metal thin film such as Co-Ni, Co-Cr, Co-O, Co-Ti, and Co-Ni-O. Reference numeral 3 denotes a protective layer in which a plasma polymerized film, SiO ₂ , etc., and a lubricant such as a fatty acid, perfluoropolyether or the like are laminated. [JP-A-61-224128, JP-A-61-224128]
139919, JP-A-61-5426].

The magnetic recording medium shown in FIG. 2 which is expected to be particularly improved in recent years is characterized in that a hard protective film is provided to improve the durability (Japanese Patent Application Laid-Open Nos. 61-126627 and 61-126627). At present, the film thickness is about 200 mm and durability is secured in consideration of spacing loss.

However, in the above configuration, the recording wavelength is 0.5 μm.
When the thickness is less than m, there is a problem that the spacing loss is too large at a film thickness of 200 °, and there is a problem that a dropout and an error rate in digital recording are increased in some places, and improvement has been desired. The present invention has been made in view of the above-mentioned circumstances, and provides a magnetic recording medium in which dropout is improved without improving spacing loss and reducing durability.

Means for Solving the Problems In order to solve the above-mentioned problems, the magnetic recording medium of the present invention is provided with a diamond-like hard carbon thin film on a ferromagnetic metal thin film, wherein the diamond-like hard carbon thin film is It has a nitrogen ion implanted layer on the surface.

Effect The magnetic recording medium of the present invention has the above-described configuration, in which the hardness of the diamond-like hard carbon thin film is higher at the surface in the thickness direction, so that the entire thickness can be made as durable as possible, so that the spacing loss is reduced. Can be improved,
Since the surface electrification is alleviated by nitrogen implantation, fine dust adheres little and the error rate is stabilized.

Embodiment Hereinafter, an embodiment of the magnetic recording medium 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 one embodiment of the present invention. In FIG. 1, 4
Are polyamides, polyether ether ketone, polyether sulfone, a polymer film such as polyethylene naphthalate, 5 _{Al 2 O 3, ZnO, TiO} 2, polyethylene balls,
This is a fine particle coating layer on which polyimide spheres and the like are arranged. 6 is Co
-O, Co-Os, Co-Ti, Co-Cr, Co-Mo, Co-Ru, Co-Ni, Co-
Ferromagnetic metal thin films such as Ni-P, Co-Ni-O, Co-Cr-Nb, and Co-Cr-Nd. Electron beam evaporation, high frequency sputtering, ion beam deposition, ion plating, etc. Formed by 7 is a diamond-like hard carbon thin film having a nitrogen ion implanted layer 8 on the surface.
The formation of the diamod-like hard carbon thin film is performed by a method of accelerating the plasma of a hydrocarbon gas, a method of sputtering graphite on a target, an ion beam deposition method, etc., and the ion implantation is performed using nitrogen ions of 5 KeV to 50 KeV at 10 μA / Injection may be performed at cm ^{2 to 1} mA / cm ² .

Reference numeral 9 denotes a lubricant such as a fatty acid, a fatty acid amide, a perfluorocarboxylic acid, or a perfluoropolyether, which is formed by a solution coating method, a vacuum deposition method, or the like.

The magnetic recording medium of the present invention can be embodied in any of a magnetic disk and a magnetic tape.

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

Cr ₂ O ₃ fine particles with a diameter of 150 mm are arranged on a 10 μm-thick polyethylene terephthalate film, and Co-Cr-B (Co: Cr: B = 79: 18: 3, atomic% ratio) is applied thereon by high frequency sputtering. Ar + H ₂ = 0.08 (Torr) Ar: H ₂ = 1: 3,13.
Sputtering under conditions of 56 (MHz) 1.1 (KW), 100
A diamond-like hard carbon thin film of 配 is arranged, nitrogen ions are implanted thereon at 20 KeV, 120 μA / cm ² , and furthermore, perfluoropolyether “Fomblin Z-25” manufactured by Montefluos by vacuum evaporation. Were arranged in an angle of 60 mm and processed into a magnetic tape having a width of 8 mm.

On the other hand, in the comparative example, a diamond-like hard carbon thin film was arranged without nitrogen ions being implanted.

The recording wavelength of 0.49 μm was recorded by a metal head with a gap length of 0.19 μm using an 8 mm video modified from each tape, and the C / N and dropout were compared. Drop-out is 3.75m / sec relative speed between head and tape.
(Μsec) and -10 (dB) per minute.

The initial C / N of Comparative Example A and Example was the same, and Comparative Example B was
It was -2.9 (dB) for them. In the example, dropout was measured for 100 minutes and averaged 80 pieces / min, maximum 10 pieces.
Comparative example A was 98 / min on average and 720 / max.
min, Comparative Example B had an average of 120 pieces / min and maximum of 1205 pieces / min. Still durability was 55 minutes for the Example, and 30 minutes for Comparative Example A, which was the time until noise became noticeable by visual observation of the image. Comparative Example B is 56
Minutes. From the above results, it can be seen that the example can improve the C / N and the dropout performance without reducing the durability.

Effects of the Invention As described above, according to the present invention, there is an excellent effect that a magnetic recording medium excellent in both high density recording performance and durability can be obtained.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of a magnetic recording medium according to one embodiment of the present invention, and FIG. 2 is an enlarged sectional view of a conventional magnetic recording medium. 4 ... polymer film, 5 ... fine particle, 6 ... ferromagnetic metal thin film, 7 ... diamond-like hard carbon thin film, 8 ... nitrogen ion implanted layer.

Claims (1)

(57) [Claims] 1. A magnetic recording medium comprising a diamond-like hard carbon thin film disposed on a ferromagnetic metal thin film, wherein the diamond-like hard carbon thin film has a nitrogen ion implanted layer on the surface.