JPS61199229A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve the crystal orientation and magnetic characteristic of a magnetic layer and to increase the number of times of CSS by providing a nonmagnetic underlying layer consisting of one kind among VC, VC2 and VN between a nonmagnetic hardened layer and magnetic medium layer. CONSTITUTION:An alumite film is coated as the nonmagnetic hardened layer 2 to about 4mum on a disk-shaped aluminum alloy substrate 1. After the film is finished to a specular surface, the coating consisting of one kind among VC, VC2 and VN is formed as the nonmagnetic underlying layer 3 thereon to the thickness ranging 50-2,400Angstrom and a thin gamma-Fe2O3 film is formed as the magnetic medium layer 4 thereon. The adverse effect of the nonmagnetic hardened layer 2 is prevented and the crystal orientation and magnetic characteristic of the magnetic layer are improved by providing the nonmagnetic underlying layer 3 consisting of, for example, the VC film in the above-mentioned manner. The increase in the number of times of CSS is thus made possible.

Description

[Detailed description of the invention] [Industrial application field] This invention applies to fc such as cobalt and cobalt alloys.

The present invention relates to a magnetic recording medium having a magnetic layer made of a metal ferromagnetic material such as iron, iron alloy, nickel, or nickel alloy, or a magnetic layer made of a metal oxide ferromagnetic material such as iron oxide or chromium oxide.

[Conventional technology]

In recent years, the importance of external storage devices such as magnetic disks in computer systems has increased, and the demand for higher recording densities is increasing.

A magnetic recording device is composed of the main components of a recording/reproducing head and a magnetic disk. The magnetic disk rotates at high speed, and the recording/reproducing head floats a minute distance above the magnetic disk.

As the performance of magnetic recording devices improves, the load on the recording/reproducing head is reduced in order to reduce the flying distance, and contact start/stop (contact start/stop: c
ss) type head flotation system is adopted. In order to increase the recording density and performance of magnetic disks, that is, magnetic recording media, it is necessary to make the recording media thinner, more uniform, and improve the magnetic properties (improvement of coercive force and squareness ratio).

In addition, it is necessary to improve the precision of the disk surface and the head crash resistance in order to ensure a stable head flying state in low-flying systems and prevent collisions between the head and the disk (head crash).

Accordingly, it has become important to improve the quality of the substrate that supports the magnetic medium layer.

Conditions for a substrate suitable for high-density recording include good mechanical flatness and surface roughness, and a small number of defects. Furthermore, as the recording medium becomes thinner, the substrate needs to have sufficient hardness. In other words, if the substrate is soft, it will cause deformation such as depression when the magnetic head is connected to the magnetic disk, and not only will the magnetic head not be able to achieve a stable floating state, but also the contact start stop, which indicates the reliability of the magnetic recording device. (C88) There is a problem that the number of times becomes small.

Traditionally, aluminum alloys have been used for the substrates of magnetic disks because of their surface hardening and surface precision.

A hardened layer is coated thereon. For this hardened layer, N1-P plating or alumite film with good abrasiveness has been used (for example, Electric Corporation Research and Practical Application Report Vol. 31, No. 9, pp. 1731-1744, Prior Art Patent Application No. 1973- 8863
No. 3 9% Application No. 111468/1989). After forming this film, two machining processes are performed to improve the surface precision and form a magnetic medium layer. There is a close relationship between the magnetic properties and crystal orientation of this magnetic medium layer, and it is known that the crystal orientation is influenced by the type of underlying film of the magnetic medium layer (for example, Ota et al. A collection of academic lecture summaries from the Japan Society of Applied Magnetics.

15pB-8 (1984)) for example, 1-Fe
It is known that the magnetic properties are better when the 2O3 thin film has the [111] orientation, and when the Co and 00 alloy thin films have the C-axis orientation.

[Problem that the invention seeks to solve]

However, when forming a magnetic medium layer by forming various hardened layers, in most cases the desired crystal orientation is not obtained, and as a result, the magnetic properties do not improve, such as the squareness ratio S determined from the magnetization curve worsening. There was a problem.

This invention was made to solve the above-mentioned problems, and has good crystal orientation, that is, magnetic properties, and
The purpose is to obtain a highly reliable magnetic recording medium that can be used repeatedly.

[Means for solving problems]

The magnetic recording medium of the present invention has a nonmagnetic underlayer made of one of V Cm VC2# and VN formed between the nonmagnetic hardened layer and the magnetic medium layer.

[For production]

By forming a nonmagnetic underlayer made of any one of VC, VC2, and VN according to the present invention.

It is possible to prevent the negative effects of the non-magnetic hardened layer, improve the crystal orientation of the magnetic medium layer, and not reduce the hardness and good surface precision properties of the non-magnetic hardened layer.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, numeral 11 is an aluminum alloy substrate which is a non-magnetic substrate, (2) is a non-magnetic hardened layer, (3) is a VC non-magnetic underlayer, and (4) is a magnetic medium layer.

This invention will be explained in more detail below with reference to specific examples, but the invention is not limited thereto.

EXAMPLE A disk-shaped affluminium alloy substrate (1) was coated with an alumite film having a thickness of 4 μm as a nonmagnetic hardened layer (2).

After mirror finishing the alumite film, non-magnetic underlayer (3)
A VC film was formed by a reactive sputtering method.

Furthermore, samples of OVC# having different film thicknesses in which a γ-F'e205 thin film was formed as the magnetic medium layer (4) were prepared, and nine different measurements were performed, and the results are summarized in a table. The crystal orientation was measured by +XS diffraction method.
Beep in 22 directions! It is expressed by the ratio of the peak I in the (22□) and 311 directions. The angular swelling ratio S is calculated from the magnetization curve.

Furthermore, FIG. 2 shows an example of changes in the thickness of the non-magnetic underlayer and each characteristic value when the non-magnetic underlayer is VC.

An example in which the nonmagnetic underlayer is VN is shown in FIG. In the figure, 9 curves 11 represent changes in 1(222)/l (311), 1 curve 12 represents changes in S, and 9 curves 13 represent changes in the ratio of 089 times.

Note) Expressed as a ratio, with the number of CSSs when the VC film is QA [not formed] as 1.

As is clear from the table and Figure 2, the film thickness of VC is 5O
When A is exceeded, the crystal orientation and the S value improve. On the other hand, when the VC film thickness exceeded 240 OA and became 30 GOA or more, 088 deteriorations were given.

It is considered that if the VC film thickness is too thick, the effect of the nonmagnetic hardened layer will be weakened, leading to a worsening of the 088 times.

Moreover, if it is over 300 OA, cracks will often occur due to the difference in the coefficient of thermal expansion, so 300 OA or more is not desirable.

In the above embodiment, the case of VC film was explained, but V
Similar results are obtained even in the case of C2 and VN, and the same effects as in the above embodiment are obtained.

〔Effect of the invention〕

As described above, according to the present invention, a non-magnetic substrate.

a nonmagnetic hardened layer coated on the nonmagnetic substrate; a nonmagnetic underlayer made of any one of VC, VC2, and VN coated on the nonmagnetic hardened layer; With a coated magnetic media layer.

This has the effect of improving crystal orientation and magnetic properties, increasing the number of CSS operations, and providing a highly reliable magnetic recording medium.

Also, vc, vc2. When the thickness of the non-magnetic underlayer made of any one of VN and VN is set to 50 to 240 d, the above-mentioned effects are enhanced.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a magnetic recording medium obtained by an embodiment of the present invention, and FIGS. 2 and 3 are characteristic diagrams showing changes in the film thickness of the nonmagnetic underlayer and each characteristic value. be. (1)...Nonmagnetic substrate, (2)...Nonmagnetic hardened layer,
(3)...VC nonmagnetic underlayer, (4)...magnetic medium layer.

Claims (2)

[Claims] (1) A non-magnetic substrate, a non-magnetic hardened layer coated on this non-magnetic substrate, VC, VC coated on this non-magnetic hardened layer
A magnetic recording medium comprising a nonmagnetic underlayer made of any one of _2 and VN, and a magnetic medium layer covered with the nonmagnetic underlayer. (2) The thickness of the non-magnetic underlayer formed from any one of VC, VC_2 and VN is 50 to 2400 Å.
The magnetic recording medium according to claim 1, characterized in that the magnetic recording medium is within the range of .