JPH0697497B2 - Magnetic recording medium - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium having a perpendicularly magnetized film which can be used for high density magnetic recording as a magnetic recording layer.

2. Description of the Related Art In recent years, there has been a strong demand for magnetic recording to improve its recording density as its applications have expanded, and in response to shorter wavelengths and narrower tracks,
Signal-to-noise together with absolute output magnitude (hereinafter referred to as SN)
Improvement and development of a medium having a good ratio and a magnetic head having a good recording / reproducing efficiency are under way. In particular, attention has recently been paid to using a ferromagnetic metal thin film as a magnetic recording layer. A so-called metal thin film magnetic recording medium, in which the easy axis of magnetization is oriented in the vertical direction, is considered to be particularly promising for high density, and research and development has been actively conducted.

Recently, in perpendicular recording / reproducing, the possibility of recording / reproducing at a recording wavelength of 0.3 μm or less has come to be seen even with a ring type magnetic head which has been conventionally used, and the efforts toward practical use are accelerated. ing.

A medium suitable for these is a single layer directly on the polymer film.
A layer of Co-Cr perpendicularly magnetized film or a layer of C via a Ge film
An example is one in which an o-Cr perpendicular magnetic film is arranged. [For example, Journal of Television Society, Vol.39, No.4, PP357-364 (198
5) Reference] Problems to be Solved by the Invention However, in the configuration as described above, when the recording density is increased, the rate of error occurrence increases when recording and reproducing under various environmental conditions are combined, The improvement of recording density has a problem that it does not reach the level achieved under a certain environment.

In view of the above problems, the present invention provides a magnetic recording medium capable of achieving high density recording with a good S / N and a small error rate even under various environments.

Means for Solving Problems The magnetic recording medium of the present invention for solving the above problems,
The first layer of columnar crystal fine particles constituting the magnetic recording layer is vertical on the substrate side and curved on the terminal side, and the second layer formed thereon is almost vertical, and the interparticle gap is 90% or more. It has a perpendicular magnetic layer which is a continuous perpendicular magnetic layer.

Action According to the present invention, the curved portion acts like an in-plane magnetized film by dividing the perpendicular magnetization of the first layer and the second layer by the above-described configuration, and the magnetic domain apparently appears. As it becomes smaller, noise is improved and S / N
Is improved and the gap is reduced to 10% or less, the moisture permeability of the magnetic recording layer is reduced, the stress relaxation phenomenon at the interface between the first layer and the substrate is less affected by the environment, and the dimensional change is almost eliminated. Therefore, even if the track is narrowed, it is possible to record and reproduce with a small error rate.

Examples Hereinafter, magnetic recording media according to examples of the present invention will be described with reference to the drawings.

FIG. 1 is an enlarged sectional view of an example of the magnetic recording medium of the present invention. In FIG. 1, 1 is a polymer film (substrate) made of a polyethylene terephthalate film having a thickness of 12 μm, 2 is a magnetic recording layer, which is divided into a first layer 3 and a second layer 4, and the first layer 3 is Co—Cr. (Cr; 20.2wt%), thickness
Electron beam evaporation was started with a component close to vertical at 0.09 μm, and the mask was adjusted to include a little oblique component as the thickness increased, and the incident angle was 3 to 24 degrees. The range was set. The can temperature during vapor deposition was 130 ° C. The second layer 4 is also a Co-Cr film with a thickness of 0.08 μm.
The incident angle was composed of only vertical components within 3 degrees.

As for magnetic characteristics, the coercive force in the vertical direction was 670 (Oe), and the half-width of the rocking curve of the X-ray diffraction line (002) was 6 degrees.
Reference numeral 5 is a lubricant layer formed by vacuum deposition of about 65 liters of perfluorooctanoic acid.

FIG. 2 is a partially enlarged sectional view of the magnetic recording layer 2 of FIG. In FIG. 2, 1 is a polymer film (substrate), 6
Is a columnar crystal fine particle of the first layer 3, 6G is a gap between the particles, and 6 is vertical on the substrate side and curved on the terminal side. Therefore, 6G is not configured linearly. 7 is a columnar crystal fine particle of the second layer 4, and 7G is a gap between these particles. Although No. 7 was grown vertically, it is naturally permissible that it is slightly curved near the surface in the range where the vertical orientation is good.

As shown schematically in Fig. 2, 6G and 7G are almost discontinuous, and if 90% or more are discontinuous when observed with a scanning electron microscope, the surface 1S of the polymer film will be described later. Since the stress relaxation phenomenon near is stable without being affected by the environment, the dimensional change of the medium can be ignored.

As a comparative example, a Co-Cr (Cr; 20.2 wt%) film having a thickness of 0.17 μm was formed using the same polymer film substrate, and the same lubricant layer was arranged on the film.

Recording wavelength of 0.45μ on a track of 7μm with the product of the present invention
Recorded and played back at m. The S / N of the product of the present invention was 3.6 dB higher. The error rate is shown as a relative ratio, with the level that can be corrected being 1. The following table shows the error rates when recording was performed at 20 ° C and 60% RH, then stored for 1 month under various conditions, and then reproduced again in the environment of 20 ° C and 60% RH.

As is clear from the above table, the product of the present invention has a level at which the error rate can be corrected irrespective of the environment, but the conventional product has a level of 10 times or more the level that can be corrected depending on the environment and is not practical.

Although the polymer film is polyethylene terephthalate in this embodiment, it may be polyamide, polyimide, polyphenylene sulfide, polycarbonate or the like.

The perpendicular magnetization film was a Co-Cr film, but Co-V, Co-Ti, Co-W, C
You may comprise o-Mo, Co-Cr-Nb, or the first layer and the second layer in any combination thereof.

As described above, in the magnetic recording medium of the present invention, since the dimensional change of the recording medium is small irrespective of the storage environment, the error rate is reduced by the high density recording / reproducing by narrowing the track and shortening the wavelength. It has an excellent effect that it can be done.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of an embodiment of the magnetic recording medium of the present invention, and FIG. 2 is a partially enlarged sectional view of the embodiment of the present invention. 1 ... Polymer film, 2 ... Magnetic recording layer, 3 ... First
Layer, 4 ... Second layer, 5 ... Lubricant layer, 6,7 ... Columnar crystal fine particles, 6G, 7G ... Gap.

Claims (1)

[Claims] 1. A first layer of columnar crystal fine particles constituting a magnetic recording layer is vertical on the substrate side and curved on the terminal side, and a second layer formed thereon is substantially vertical, and the interparticle gap is formed. But
A magnetic recording medium having a perpendicular magnetization layer which is discontinuous by 90% or more.