JPH01199314A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To form the crystal grains of a magnetic metallic layer to the finer grains so that high-purity recording is enabled by providing an under coat layer contg. specific components on a substrate and providing an intermediate layer contg. chromium on the under coat layer, then providing a magnetic layer on the intermediate layer. CONSTITUTION:The under coat layer contg. the components selected from the group consisting of carbon, aluminum, titanium, cobalt, copper and niobium is provided on the substrate. Namely, the film contg. the components selected from the group consisting of the carbon, aluminum, titanium, cobalt, copper and niobium is formed to 500-5,000Angstrom , more preferably 500-3,000Angstrom film thickness on the substrate. The formation of this film is executed by a sputtering method. The film of the intermediate layer contg. the chromium is then formed to 500-10,000Angstrom film thickness on the under coat layer under the same conditions. The film of the magnetic metallic layer is then formed to 200-2,000Angstrom film thickness on the intermediate layer under the same conditions as the conditions of the sputtering method. The crystal grains of the magnetic metallic layer are thereby formed to the finer grains and the magnetic recording medium suitable for high-density recording is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording medium such as a magnetic disk used for magnetic recording and the like.

[Prior art and its issues]

In recent years, there has been a trend toward higher density recording in magnetic recording media, and it is necessary to increase coercive force and S/N ratio.

A non-magnetic metal underlayer (e.g. Cr) is formed on the substrate by sputtering, followed by a magnetic metal layer (e.g. Co).
-Ni, Co-Ni-Cr) magnetic recording media made of multilayer films formed by similar methods are generally well known. In order to increase the coercive force of a magnetic recording medium having such a layered structure, the length can be increased by increasing the thickness of the non-magnetic metal underlayer or by decreasing the thickness of the magnetic metal layer. However, when the non-magnetic metal underlayer is made thicker, the crystal grains become coarser, and the crystal grains of the magnetic metal layer epitaxially grown on it also become coarser, resulting in S/N
ratio decreases. Furthermore, if the magnetic metal layer is made thinner, the residual magnetic flux density (Sr) decreases, resulting in a problem of insufficient output.

[Means to solve the problem]

As a result of extensive studies, the present inventors found that by providing an undercoat layer containing a component selected from the group consisting of carbon, aluminum, titanium, cobalt, copper, and niobium on the substrate,
The inventors have discovered that by making the crystal grains of the non-magnetic metal layer finer, and by making the crystal grains of the continuously sputtered magnetic metal layer finer, a magnetic recording medium suitable for high-density recording can be obtained, and the present invention has been achieved.

That is, the gist of the present invention is to provide an undercoat layer containing a component selected from the group consisting of carbon, aluminum, titanium, cobalt, copper, and niobium on a substrate, and to deposit C on the undercoat layer.
A magnetic recording medium includes an intermediate layer containing r and a magnetic layer provided on the intermediate layer.

The present invention will be explained in detail below.

The substrate used in the present invention is an aluminum alloy substrate plated with NiP. The NiP plating film was deposited on an aluminum alloy substrate with a thickness of 20 μm using a known electroless plating method.
A film is formed to a film thickness of 1.5"-2s pm.Then, the substrate surface is mechanically polished to an Ra (center line average roughness) of 20.
A~,? Finish to OA.

In the present invention, an undercoat layer containing a component selected from the group consisting of carbon, aluminum, titanium, cobalt, copper, and nimeb is provided on the substrate. Specifically, a film containing a component selected from the group consisting of carbon, aluminum, titanium, cobalt, copper, and niobium is deposited on a substrate at 30θA-! 0OOA, preferably 1! 00A S-3000ACD film is formed to an expanded thickness.

The film is formed by a commonly used sputtering method. For example, it is performed using a DC sputtering device or an AC sputtering device, and the inside of the device on which the substrate is mounted is pre-coated with /
Evacuate to 1O-5 torr or less, and use argon as a sputtering gas at a partial pressure of j x 10-3 to II
10-'' torr and heat the substrate in a range from room temperature to 200°C.

It is desirable that targets such as carbon, aluminum, titanium, cobalt, copper, and niobium have high purity;
Other metals may also be included in the O-Sθ atoms. This undercoating layer is important for making the crystal grains of the intermediate layer and the magnetic metal layer fine, and it is desirable that the surface on which it is formed is dense.

Next, an intermediate layer containing chromium is formed on the undercoat layer under the same conditions as the above sputtering method! ;001k.

Although the film is formed to a thickness of ~1ooooh, a film thickness of 1000A-jθθoA is desirable for use in high-density recording. The target is mainly composed of chromium and may also contain 0-10 atoms of other metals.

Next, a magnetic metal layer is formed on the intermediate layer to a thickness of 2oθAA-koθoool under the same conditions as the above sputtering method. The magnetic metal layer has cobalt as its main component, and may also contain other metals such as nickel, chromium, and platinum. As a target, for example, CogO atom Qi Ni
Co0 atom, Co7 da atom%-Nilt atom%-Crg
Atom Q, CoA2. ! ; atomic%-Ni30 atomic%-C
Those with r7.3 atoms are generally used.

In the magnetic recording medium manufactured in this way, the crystal grains of the magnetic metal layer can be made finer than in a medium without an undercoat.

〔Example〕

The present invention will be explained below with reference to Examples, but the present invention shall not be limited by the Examples unless it goes beyond the gist of the invention.
do not have.

Example 1 A NiP-plated aluminum alloy plate top plate, undercoat layer, intermediate layer, and magnetic metal layer were continuously sputtered under the following conditions under an argon atmosphere using a direct current type magnetron sputtering device.

Initial exhaust 1~CoX10''torr Argon partial pressure /
Target layer for intermediate layer) Cr (purity 99.9% or higher) Target layer for magnetic metal layer) Coqa atomic % - Ni/f atomic Qi Cr Zn sublayer film thickness: approx. 1000 Intermediate layer film thickness: approx., yoool Magnetic metal Layer thickness approximately 600).

The results are shown in Table 1.

Example 1 The same procedure as Example 1 was carried out except that copper (purity: 100% or higher) was used as the target for the undercoat layer. The results are shown in Table 1. The S/N ratio was 3 J, OdB, which was improved by 8.1-dB compared to the comparative example described below.

Example 3 The same procedure as Example 1 was carried out except that niobium (purity of 99.9% or more) was used as the target for the undercoat layer.

The results are shown in Table 1.

The S/N ratio was 3 y, 2 dB, which was improved by 2.7 dB compared to the comparative example described below.

Example 1 The same procedure as Example 1 was conducted except that titanium (purity 99.94 or higher) was used as the target for the undercoat layer.

The results are shown in Table 1.

Example S Aluminum (purity 99
．． 94 or higher) was used in the same manner as in Example/. The results are shown in Table 1. The S/N ratio is 311.
t dB, which is 3. ! ; improved by dB.

Example 6 Carbon (purity 9?, 9?9%) as target for undercoat layer
) was used in the same manner as in Example/. The results are shown in Table 1. The S/N ratio is 1.33. ! ;dB, which is an OdB improvement compared to the comparative example described below.

Comparative Example The same procedure as in Example was carried out except that the undercoat layer was not formed. The results are shown in Table 1. The S/N ratio was 38 dB.

Table 1 As shown in Table 1, the crystal grains of the magnetic metal layer with the trap and underlayer are finer than those without the underlayer.

〔Effect of the invention〕

According to the present invention, since the crystal grains of the magnetic metal layer can be made finer, it is possible to provide a magnetic recording medium suitable for high-purity recording.

Claims (1)

[Claims] (1) An undercoat layer containing a component selected from the group consisting of carbon, aluminum, titanium, cobalt, copper, and niobium is provided on a substrate, an intermediate layer containing chromium is provided on the undercoat layer, and an intermediate layer containing chromium is provided on the undercoat layer. A magnetic recording medium that has a magnetic layer on top of the magnetic layer.