JPH0758538B2 - Magnetic recording body and manufacturing method thereof - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a perpendicular magnetic recording medium, particularly a magnetic recording medium.

(Prior Art) Improvement of the recording density of a magnetic recording device is a constant trend in the field. As a magnetic recording medium used here, a so-called coating medium in which iron oxide fine particles are dispersed and applied in a resin has been conventionally used. Long-term recording of Co alloys (magnetization is in-plane) made by plating or sputtering in recent years, and recording is performed by forming unevenness on the surface and generating anisotropy in the stripe direction to improve magnetic characteristics. Improves density characteristics. On the other hand, a perpendicular magnetic recording medium represented by a CoCr medium similarly produced by a sputtering method or a vapor deposition method has been proposed, and a recording density exceeding the above-mentioned longitudinal recording has been achieved.

In this perpendicular magnetic medium, the inventors of the present invention presented the surface roughness on the substrate at the 45th Annual Meeting of the Japan Society of Applied Physics (Proceedings P372).
It was reported that an in-plane easy axis is generated in the stripe direction by forming stripe unevenness with Rmax of about 1000Å or more.

(Problems to be Solved by the Invention) In a longitudinal recording medium, in order to achieve a steep magnetization transition without disturbing the magnetization due to a demagnetizing field generated when recording is performed by a magnetic head, anisotropic magnetization in the longitudinal direction is required. It imparts properties and increases coercive force. On the other hand, in a perpendicular recording medium, good perpendicular anisotropy is imparted so that a demagnetizing field is not generated in the longitudinal direction to achieve high density recording. However, when the perpendicular anisotropy is relatively small, in-plane magnetization of the longitudinal component is generated and the recording density is deteriorated. Therefore, in order to prevent the generation of tangential magnetization in the longitudinal direction, in-plane anisotropy may be imparted at right angles to the longitudinal direction, and in-plane anisotropy can be imparted by forming the surface shape as in the above-mentioned document. . However, from the viewpoint of the smoothness of the recording material,
When the surface roughness is 1000 Å or more, it is difficult to guarantee reliability because the recording density characteristics deteriorate due to the increased spacing between the medium and the head, and friction and wear increase due to sliding with the head. If it becomes too large, the perpendicular magnetic anisotropy deteriorates. Further, in order to achieve this object from the viewpoint of substrate processing, it is necessary to form irregularities on the substrate at right angles to the circumferential direction, which is a difficult surface to process.

An object of the present invention is to provide a magnetic recording medium and a method for manufacturing the same which solves this problem.

(Means for Solving Problems) The gist of the present invention is that in a magnetic recording body in which a magnetic film having perpendicular magnetic anisotropy is formed on a substrate, a direction perpendicular to a recording track in the film surface of the magnetic film. A magnetic recording material having anisotropy in the direction of the surface, and after forming grooved or streak-shaped irregularities having a surface roughness in the range of 10Å to 800Å on the substrate, a magnetic film having perpendicular magnetic anisotropy is formed on the substrate. It is a method of manufacturing a magnetic recording body formed on the top.

(Function) The present invention was made by finding for the first time that magnetic anisotropy can be generated in the direction perpendicular to the groove or stripe direction, unlike the conventional method, by forming the groove or stripe unevenness having a predetermined surface roughness. It is a thing.

(Embodiment) The constitution of the present embodiment in which a magnetic film 2 having perpendicular magnetic anisotropy is formed on a substrate 1 in which grooves and streaks are used in the present invention, as shown in FIGS. 1 and 2, respectively. Indicates.

As the substrate shown here, a substrate in which a pattern is formed by a resist and unevenness is formed by an ion etching method, or a plastic material which is molded by injection using a mold in which unevenness is formed is used.

FIG. 3 shows CoCr perpendicular magnetic anisotropy in the same sputtering on the substrate 1 on which unevenness is formed with various surface roughness t as shown in FIG. 1 by the reactive ion etching method in which a pattern is formed on a SiO ₂ substrate with a resist. The relationship between the in-plane anisotropic magnetic field constant Ku of a recording medium having a thin film (thickness of 0.3 μm) and the height t of the unevenness is shown. The pitches A and B of the irregularities shown in FIG. 1 were 1.0 μm and 1.0 μm, respectively.

When the surface roughness t is about 1000 Å or more, when the groove direction is parallel to the magnetic field direction and θ = 0 °, in-plane anisotropy with the easy axis in the groove direction shown in the torque curve shown in FIG. 4 occurs. When the surface roughness t is from 10 Å to 800 Å, in-plane anisotropy with an easy axis perpendicular to the groove direction shown in the torque curve shown in FIG. 5 occurs.

(Effect of the Invention) As described above, magnetic recording having magnetic anisotropy at right angles to the groove direction is provided by forming groove or stripe unevenness in the surface roughness practically used as a magnetic recording medium. By setting the recording track parallel to the groove direction, the in-plane component of the magnetization of the bit recorded by the magnetic head does not abut each other at the bit boundary, and a sharp magnetization transition is achieved to improve the recording density characteristic. To do. Further, the substrate can be processed concentrically on the disc disk, which is preferable from the viewpoint of processing.

[Brief description of drawings]

1 and 2 are configuration diagrams of a magnetic recording medium of the present invention, in which 1 is a substrate, 2 is a perpendicular magnetic anisotropic medium, and FIG. 3 is a surface roughness of a groove and a magnetic anisotropy constant. Diagram showing the relationship between the 4th and 5th
The figure shows a torque curve.

Claims (2)

[Claims] 1. A magnetic recording body having a magnetic film having perpendicular magnetic anisotropy formed on a substrate, wherein the surface roughness is
A magnetic recording medium, characterized in that grooves or streaks in the range of 10 Å to 800 Å are provided in the same direction as the recording tracks in the film surface of the magnetic film. 2. A method for forming a magnetic film having perpendicular magnetic anisotropy on a substrate after forming grooves or streaks having a surface roughness in the range of 10Å to 800Å on the substrate in the recording track direction. A method for manufacturing a characteristic magnetic recording medium.