JPH0223512A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve durability and wide band C/N by disposing a perpendicularly magnetized Co alloy film on a high-polymer film and partially forming projections consisting of nitrogen ion-implanted parts to the surface layer part thereof, then providing a protective layer thereon. CONSTITUTION:The perpendicularly magnetized film 2 consisting of the Co alloy such as Co-Cr, Co-Ti or Co-Ta is formed on the high-polymer film by an ion plating method, sputtering method, electron beam vapor deposition method, etc. The projections 3 consisting of the ion implanted parts are partially formed thereon by executing nitrogen ion implantation and thereafter, the protective layer 4 is provided. The height of the projections 3 is preferably 30-100Angstrom . These fine projections 3 decrease the contact surface under head sliding and relieve friction. In addition, the projections 3 themselves are the nitride and hard; therefore, the durability is assured even if the film thickness of the protective layer 4 is reduced. Since the projecting parts can be constituted as the perpendicularly magnetized film as well, the increase of the noises is eventually prevented and the C/N is maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a high-density magnetic recording medium having a magnetic recording layer made of a Co-based alloy perpendicularly magnetized film.

BACKGROUND OF THE INVENTION Since perpendicular magnetic recording has low loss during high-density recording, it is expected to be a recording technology that can realize information exchange with a pit area of 1 (μm) Xl (μm) in the future.

However, when looking at today's technology from a practical standpoint, there remains a problem to be solved, typified by the problem of partial destruction and damage to the magnetic recording medium when the head slides. Currently, Co-
Research on perpendicular magnetization films, represented by 0r, has been conducted mainly using sputtering methods, and attempts have been made to improve media damage by changing film formation conditions [Proceedings of the 29th Spring Conference of the Japanese Society of Lubricants, p. 377 (1985 )) Appropriate protective film [46th Research Meeting of Japan Society of Applied Magnetics, pp. 46-7.57 (1986
)) and surface properties to confirm the effectiveness of reducing protrusions [Magnetic Recording Research Group Materials MR87-46, page 9 (1es
y)) etc., and improvements have been made by using lubricants in combination.

Problems to be Solved by the Invention However, at present, in order to obtain sufficient durability, the thickness of the protective film becomes thicker, and the advantages of perpendicular magnetic recording are lost due to spacing loss, which has a larger effect as the wavelength becomes shorter. There were some issues such as poor performance, and improvements were desired.

The present invention was made in view of the above-mentioned circumstances, and provides a magnetic recording medium for perpendicular magnetic recording that has improved both durability and broadband 07H.

Means for Solving the Problems In order to solve the above-mentioned problems, the magnetic recording medium of the present invention has a Co-based alloy perpendicularly magnetized film disposed on a polymer film, and protrusions made of nitrogen ion implanted portions are partially formed on the surface layer. A protective layer is disposed on top of the protective layer.

Function The magnetic recording medium of the present invention has the above-described structure.The fine protrusions reduce the contact area under the sliding head and soften the friction.The protrusions themselves are made of nitride and are hard, so the thickness of the protective layer can be reduced. Even if it is made thinner, durability can be ensured, and the protrusion can also be configured as a perpendicularly magnetized film, which prevents an increase in noise and maintains C/N.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. The figure is an enlarged sectional view of a magnetic recording medium according to an embodiment of the present invention. In the figure, 1 is polyethylene terephthalate.
Polymer films such as polyphenylene sulfide, polyether sulfone, polyamide, polyether ether ketone, etc., average roughness is 10 to 50 A, maximum roughness is 30
It is preferable to have a smooth surface of 1 to 100 mm.

2 is Go-Or, (jo-Ti, Co-Ta
, Co-0r-WbOo-Cr-Zr, etc.
A perpendicularly magnetized alloy film, which may be combined with an underlayer of Ti, Si, Go, etc. or a soft magnetic layer of Fe-Ni, etc., if necessary.
It may be formed on both sides of the polymer film. The perpendicular magnetization film may be formed by an ion blasting method, a sputtering method, an electron beam evaporation method, or the like.

3 is a protrusion composed of an ion implantation part, which is obtained by performing nitrogen ion implantation in the energy range of 10KeV to 60KeV.The height of the protrusion is preferably 30 to 100, and when viewed as C0NX, X is 0.3-0.5
It is preferable to adjust it so that it falls within the range of 5. 0.3
Below, the hardness of the tip of the protrusion is small and the durability is insufficient.
When the value exceeds 0.56, the vertical anisotropy of the protrusion collapses and becomes a noise source, resulting in a C/N drop at extremely short wavelengths (for example, 0.4
Significant at micrometers or less. ), it is best to set it within this range.

Of course, some alloy systems act to increase hardness, so the above-mentioned Of course. 4 is plasma polymerized film, diamond thin film, fatty acid.

This protective layer is selected from known protective layers such as perfluoropolyether and is formed in an appropriate amount so as not to increase the spacing loss.

Examples of the present invention will be described in more detail below in comparison with comparative examples.

Example-1 A 0.2 μm thick Co-0r (9 wt% Co) perpendicularly magnetized film was formed on a polyethylene terephthalate film with a thickness of 10 μm and a surface roughness of 26 (maximum roughness: 65) by high-frequency sputtering, and then implanted. Diameter 0.4 μm; average density e x 1o' +/cd, protrusion height! Nitrogen implantation protrusions of OA were formed by implanting at 15 KIV and 66 μm/i. The protrusion has an X of 0.4 in terms of CoNx.

On top of this, 66 people formed a plasma polymerized film of tetramethylcyclodi7-lazan to produce a prototype magnetic tape with an 8 mm width.

Example 2 An 8 mm wide magnetic tape was prototyped with the same configuration as Example 1 except that Co-Ti (Gonia 9 wt%) was substituted for Go-Or in Example 1.

Example-3 The conditions for the nitrogen injection protrusion in Example-1 were changed to 20 and θV71μ.
Mu/C skin, injection diameter 0.6 μm, protrusion height 60 people.

An 8 mm wide magnetic tape was experimentally manufactured under the same conditions except that the average density was 4 x 106 Ad.

Comparative Example 1 An 8 mm wide magnetic tape was prototyped under the same conditions as in Example 1, except that nitrogen ions were replaced with oxygen ions to form injection projections.

Comparative Example-2 An 8-mm-wide magnetic tape was prototyped in which 5i02 fine particles with a diameter of 100 particles were arranged in 4 x 10' pieces/i on the film of Example-1, and a Co-0r perpendicular magnetization film and a plasma polymerized film were arranged thereon. did.

The still durability and broadband C/N of the above tapes were compared using a modified 8mm video tape. The head used was a laminated amorphous head with a gap length of 0.18 μm, a band of 9 (MHz), and a recording wavelength of 0.46 μm. A comparison was made under a narrow track condition with a track width of 8 μm, and the results are summarized in a table.

(The following is a blank space) In particular, there is a difference in C/N depending on the head, and care must be taken because the usefulness of the embodiment may be diminished if the head is configured to generate sliding noise.

Effects of the Invention As described above, the present invention has the excellent effect of imparting durability without impairing the recording performance of the perpendicularly magnetized film.

[Brief explanation of the drawing]

The figure is an enlarged sectional view of a magnetic recording medium according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1...Polymer film, 2...Co-based alloy perpendicular magnetization film, 3...Nitrogen ion implantation protrusion. Name of agent: Patent attorney Shigetaka Awano and 1 other person1-
11 Hatake Sho) 74 Lum 7---Cct ball meeting Tiaku) ζ Sniff 3-Nitsu Group fv3tN Tu Asahi

Claims (1)

[Claims] A magnetic recording medium characterized in that a Co-based alloy perpendicularly magnetized film is disposed on a polymer film, and a protective layer is disposed on the surface layer of which a protrusion consisting of a nitrogen-implanted portion is partially formed.