JPS60219625A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To decrease spacing loss in high-density recording in which a magnetic recording medium withstands high-speed sliding contact with a magnetic head for a long period by disposing a lubricant layer contg. fatty acid on a thin ferromagnetic metallic film constituted of the particle groups coated with a phosphorus compd. on the surface of the pulverous ferromagnetic particles. CONSTITUTION:The surface of the pulverous ferromagnetic particles constituting the thin ferromagnetic metallic film 3 which consists of Co-P, Co-Ni-P, etc. and is formed by an electroless plating method, electron beam vapor deposition method, etc. on the surface of a high polymer substrate 1 (e.g.; polyethylene terephthalate, polyamide, etc.) is coated with the phosphorus compd. to >=50Angstrom thickness. The lubricant layer 4 consists of the composite of the sputtered film and plasma-polymerized film composed of fatty acid or partly fluorinated fatty acid or the mixture composed thereof and contains at least fatty acid. The durability of the magnetic recording layer is considerably improved by the interaction of the phosphorus of the pulverous particles and the fatty acid.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording medium for high-density magnetic recording using a ferromagnetic metal thin film as a magnetic recording layer.

Conventional configuration and its problems Six years have passed since the perpendicular magnetic recording method was proposed by Professor Iwasaki of Tohoku University in 1977, and research and development has been progressing domestically and internationally as one of the main research themes for high-density magnetic recording. ing.

Most of the perpendicular magnetization films required for perpendicular magnetic recording that have been reported to date are made of CO alloys such as Co-Cy, but the manufacturing methods include sputtering, vacuum evaporation, and electroless plating. known.

According to reports so far, sufficiently high-density recording can be obtained regardless of the manufacturing method as long as the necessary conditions are met, but little is known about the practical durability of the media.

The conditions for using it as a four-way magnetic disk are harsh, and in order to prolong the high-speed sliding contact time with the magnetic head, there is a method of placing a sputter protection film of, for example, 5LO2 on the magnetic recording layer and placing a lubricant on top of it. Proposals have been made such as disposing a plasma polymerized film.

FIG. 1 shows an example of the configuration of a typical magnetic recording medium.

In FIG. 1, 1 is a polymer substrate, 2 is a soft magnetic layer such as a permalloy thin film, 3 is a perpendicular magnetization film, and 4 is a protective film.

The conventional protective film has a thickness of 0.06 μm or more, preferably 0.1 μm.
Since a thickness of more than μm was required, the spacing loss became too large and became an obstacle to short wavelength recording.
Improvements are desired.

OBJECTS OF THE INVENTION The present invention was made in view of the above circumstances, and it is an object to provide a magnetic recording medium with low spacing loss and good durability.

Components of the Invention The magnetic recording medium of the present invention is characterized in that a lubricant layer containing at least a fatty acid is disposed on a ferromagnetic metal thin film composed of a group of ferromagnetic fine particles whose surfaces are coated with a phosphorus compound. , which has little spacing loss in high-density recording that can withstand high-speed sliding contact with a magnetic head for a long time.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

The protective layer 4 in FIG. 1 contains at least a fatty acid, and other modifications may be made as necessary.

The polymer substrate used in the present invention is polyethylene terephthalate, polycarbonate, polypropylene, polyamide, polyamideimide, polyimide, or the like.

The ferromagnetic metal thin film used in the present invention can be obtained by electroless plating, electron beam evaporation, sputtering, etc.
Co-P, Go-Ni-P, Co-Ni
-Mn -P Co -Mn -Re -P, etc., and does not depend on the direction of the easy axis of magnetization, as described later.

The ferromagnetic metal thin film of the present invention has a limited fine structure, and the surface of the ferromagnetic fine particles constituting the thin film must be coated with a phosphorus compound. Figure 2 shows an example of the effect of the present invention. As mentioned above, if the thickness of the phosphorus compound is 608 or more, the effect can be obtained in a sufficiently stable manner.

The phosphorus compound does not necessarily have to be a non-magnetic and stoichiometrically perfect compound such as CORP; in short, the effect is sufficient as long as phosphorus is precipitated on the surface and is equally sparse. This is considered to be the case.

The lubricant layer of the present invention is a fatty acid or a partially fluorinated fatty acid alone or a mixture thereof, or a composite with a sputtered film or a plasma polymerized film, and the material is limited to containing at least a fatty acid, and other shall be appropriately devised in a thickness region where spacing loss is negligible (although it is probably less than 100 Å).

palmitic acid, stearic acid, myristic acid.

A fatty acid such as behenic acid can be formed on the surface by dissolving it in a solvent and applying and drying it, or by a vacuum deposition method or the like.

According to the configuration of this embodiment, durability is improved by reacting fatty acids with phosphorus to form a stable lubricant in areas where the temperature locally becomes high due to high-speed sliding contact with the magnetic head. Presumed.

A more specific example will be described below.

A Co-P thin film of 0.2 μm was formed directly on polyethylene terephthalate with a thickness of 11 μm using a high-frequency sputtering method.The resulting Co-P film had a columnar structure with a diameter of 300 mm, and the surface was coated with approximately 60,802 P. As a comparative example, a Co-Or perpendicularly magnetized film of 0.2 μm thickness was prepared by high-frequency sputtering.The conditions of the protective film were changed, and the durability of each film was evaluated. A comparative study was conducted.

As for durability, when playing with a C0-based amorphous alloy head in the stop motion mode of a hiteo tape recorder, the output is s.
Evaluation was made based on the time required for the dB' to decrease.

Note that the output was at a recording wavelength of 0.66 μm, and the initial value of the tape 1 of the present invention was o (dB).

Margin below (Note 1) As is clear from the results shown in the table, the relative output of the conventional configuration is too low, so it is unsuitable for use as a magnetic recording medium based on durability alone.

The product of the present invention is sufficiently durable in either configuration.

In Figure 2, the substrate was changed to polyamide with a thickness of 16 μm, the temperature during Co-P film formation was changed from -6°C to 166°C, the thickness of the CO2P layer was changed, and behenic acid was added to the surface. 23℃, 60%R of 40 people organically deposited
This shows the durability time at H.

As described above, according to this example, it can be seen that the durability of the magnetic recording layer is significantly improved due to the interaction between the phosphorus particles and the fatty acid.

Note that, without departing from the gist of the present invention, the present invention can be similarly applied to in-plane magnetized films formed by oblique evaporation or sputtering, regardless of the form of tape disks or sheets. The same effects as in this example have been confirmed with combinations of other p materials and manufacturing methods described above.

Effects of the Invention In the magnetic recording medium of the present invention, by disposing at least a fatty acid on a thin film composed of ferromagnetic fine particles whose surfaces are coated with a phosphorus compound, durability in high-speed sliding contact with a magnetic head is improved. It is improved over a wide range of temperature, humidity, and temperature.

[Brief explanation of drawings]

FIG. 1 is an enlarged cross-sectional view of the magnetic recording medium, and the 21st...
...Polymer substrate, 3...Ferromagnetic metal thin film, 4
······Protective film. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 - IFim Kyoui %H (A)

Claims (1)

[Claims] 1. A magnetic recording medium characterized in that a lubricant layer containing at least a fatty acid is disposed on a ferromagnetic metal thin film made up of particles whose surfaces are coated with a phosphorous compound.