JPS5977620A - Vertical magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a vertical magnetic recording medium which has excellent vertical magnetic anisotropy without depending on the material of a substrate and has improved durability by forming a vertically magnetized film on a nonmagnetic cobalt alloy film. CONSTITUTION:A nonmagnetic Co alloy consisting of Co incorporated therein with >=45wt% Ta, etc. is formed as an underlying film 5, to >=0.2mu thickness on a substrate 1 such as glass, alumina or the like. A vertically magnetized film 3 of Co-Cr, etc. is then formed on the film 5 to >=0.2mu thickness. The excellent vertically magnetized film is obtd. by the film 5 irrespectively of the material of the substrate 1 and a magnetic recording medium havint high adhesion force among the substrate 1, the film 5 and the film 3 without giving rise to peeling, etc. and having good durability is obtd.

Description

[Detailed description of the invention] The present invention relates to perpendicular magnetic recording media.

In conventional horizontal magnetic recording, as the recording density decreased, the limit was 3) to 3) kilobits per inch (abbreviated as Kbpi) due to the influence of demagnetizing fields caused by adjacent magnetizations. Perpendicular magnetic recording proposed by Professor Shun Iwasaki,
As the recording density increases, the magnetization due to the demagnetizing field decreases, and the maximum recording density is 20
It is said that 0 to 300 Kbpi is also possible.

Various configurations of perpendicular magnetic recording media have been considered depending on the application. An example is shown in FIG.

In FIG. 1 Cα), a high magnetic permeability film 2 is formed on a substrate 1,
This is the most common configuration in which a perpendicular magnetization axis 3 is formed thereon. -In order to reduce the magnetic permeability of -1i stones, per-malloy, cobalt-based amorphous materials, etc. are used.

FIG. 1 161 shows a medium 1 in which a perpendicular magnetization film 3 is formed directly on a substrate. 161 in FIG. 1 is a medium in which the pressure has been improved mainly to improve the magnetic qk properties of the perpendicular magnetization film, and an intermediate layer 4 is provided between the perpendicular magnetization film 3 and the high permeability film 20. Generally, the intermediate layer 4 is made of E3io, titanium, or the like.

The present invention relates to the basic configuration of Mr1 diagram I6). If perpendicular magnetization H~ is directly formed on the substrate as shown in FIG. 1 161, the magnetic properties will deteriorate depending on the I quality and surface properties of the substrate. To reduce the influence of the substrate, perpendicular magnetization film JL7
thicken. It is conceivable to form a non-magnetic film such as titanium on the substrate and form a perpendicularly magnetized film on top of it, but in the former case, the thinner the perpendicularly magnetized film is, the better for perpendicular magnetic recording. In the case of a system, the latter is not suitable, and the latter has a problem in the close contact with the substrate and the perpendicular magnetization axis.

Kinei 8A was developed in consideration of these points, and its purpose is to eliminate the influence of the magnetic properties by the substrate, and to create a perpendicular magnetic recording medium that has superior perpendicular magnetic anisotropy compared to single-layer perpendicular magnetization film media. The goal is to start producing.

Hereinafter, the present invention will be explained in detail based on specific examples.

Example 1 IP=M cobalt tantalum (hereinafter abbreviated as CQ-Ta) dowel marks were used as the base of the skirt magnetization film. Basics 4
1□# structure is shown in Figure 2. Ta is 45 weight - or more C,)
When mixed into the eO-Ta film, it becomes non-magnetic. Cobalt Φ chromium perpendicular magnetization film (hereinafter referred to as cO
In the present invention, a magnetic co-Ta film is used as a base layer, and a C□ -
When a Cr film is formed, co - (EfM0 thickness and CQ -Cf perpendicular magnetic anisotropy field (hereinafter abbreviated as "suke")
- is shown in Figure 3. The CQ-Tα nonmagnetic material is C
ow"a5(1(N:!t'16), and the film thickness is 0.2 μm. Ilk was measured by a torque meter. Point l116 is the characteristic of the perpendicular magnetization two-layer film. The solid line shows the characteristics of the perpendicularly magnetized two-layer film with non-magnetic CQ T (z) as the base layer.
The effect of the present invention is obvious when the -cy film is 0.3 or less.

Example? As the substrate, aluminum treated with alumina oxidation was used, and c
m: When the thickness of the Cf perpendicular magnetization film is fixed at 0.2 μm, the film thickness of nonmagnetic CQ-Ta and CQ-Cf
Figure 4 shows the relationship between the perpendicular magnetic anisotropy of the film and the magnetic field. CG is formed directly on an alumina substrate, and the film thickness is as thin as 0.2 μm.
- In the case of a CF film, there is almost no #1 perpendicular magnetic anisotropy, but when a co60TaIIo nonmagnetic film is formed on the underlying layer, as the thickness of the CQTα nonmagnetic film increases, the C0Ct- The perpendicular magnetic anisotropy of the film increased rapidly.

Note that the nonmagnetic cobalt alloy film is not limited to cobalt tantalum. In addition, non-magnetic cobalt chromium,
Non-magnetic cobalt niobium, non-magnetic cobalt tungsten,
Non-magnetic cobalt molybdenum, non-magnetic cobalt vanadium,
Non-magnetic cobalt titanium or even non-magnetic cobalt ternary system may be used. In addition, in magnetic heads with main poles and auxiliary poles facing each other, providing a high magnetic permeability film under the CQ-Cf film increases the recording and reproducing efficiency. Needless to say, the provision of the above not only increases the recording and reproducing efficiency, but also increases the perpendicular magnetic anisotropy and durability of C: and Q-Cr.

As described above, according to the present invention, the perpendicular magnetic anisotropy of the cOCg-perpendicularly magnetized film does not depend on the material of the substrate.

Co Cj - Hk > even when the film thickness is as thin as 0.2 μm
It has characteristics such as 5 KO.

[Brief explanation of drawings]

Part 1 A shows an example of the configuration of a perpendicular magnetic recording medium, Part 2
The figure shows a configuration according to the present invention. Figure 3, T, is a plot of the perpendicular magnetic anisotropy field versus the film thickness of cobalt chromium for a cobalt chromium single layer film and a cobalt chromium double layer film with non-magnetic cobalt tantalum as an underlayer according to the present invention. The figure shows the effect of the non-magnetic cobalt tantalum film thickness according to the present invention. 1. Substrate 2. High magnetic permeability film 3. Perpendicular magnetization film 4. Intermediate layer 5. Non-magnetic cobalt alloy film 6. Magnetic properties of single layer film 711. Q magnetic properties of double layer film Above application Person Suwa Seikosha Co., Ltd. Agent Patent Attorney Mogami Figure 1 Figure 2 co-(:y frls tk;ckuess
() Am) Fig. 3 0 0, (jiλ o, 3 TaketCo
-Ding”aFrl-7 kickwss (JJm) Fig. 4

Claims (1)

[Claims] A perpendicular magnetic recording medium characterized in that a perpendicular magnetization film is formed on a non-41-like cobalt alloy film.