JPH0750009A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a medium having high coercive and low noises by using a thin film medium having the alloy composition containing the specified amount of Cr and the specified amount of Mo or W as a nonmagnetic metal substrate layer. CONSTITUTION:A nonmagnetic metallic substrate layer is formed of a thin film medium having the alloy composition comprising Cr (95-60a.t.%) and one or more kinds of Mo and W (5-40a.t.%). The thickness of the Cr alloy is made to be 100-3,000Angstrom . Thus, magnetic disks, magnetic drums, magnetic tapes and the like, which satisfy both characteristics of high coercivity and low noises and can perform high-density recording, can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium such as a magnetic disk, a magnetic drum or a magnetic tape.

[0002]

2. Description of the Related Art In recent years, high recording density has been required for magnetic recording media, and continuous thin film media have attracted attention for this reason. As such a continuous thin film medium, Cr is deposited as a non-magnetic metal underlayer on a non-magnetic substrate layer, and an alloy such as CoCrTa-based or CoCrPt-based is deposited thereon as a magnetic layer by a method such as sputtering. Is configured.

For high recording density, high coercive force (hereinafter coercive force is referred to as Hc) and low noise are required.

[0004]

However, a conventional nonmagnetic metal underlayer is formed by depositing Cr and then CoCrT.
The method of forming an a-based alloy, a CoCrPt-based alloy, or the like has been insufficient in terms of high coercive force (Hc ≧ 1800 oe) and low noise. Therefore, a magnetic recording medium satisfying both high coercive force and low noise characteristics has been desired.

[0005]

In order to satisfy both of the above-mentioned high coercive force and low noise characteristics, the present invention provides a non-magnetic base layer containing Cr and at least one of Mo and W. The present invention relates to a magnetic recording medium in which a magnetic metal underlayer is formed, and the composition ratio thereof is set to one or more of Mo and W of 5 to 40 at% and the balance of Cr.

Prior to the present invention, the present inventor found that the Ar pressure was 6 mT.
orr, input power of 4 W / cm ² , substrate temperature of 230 ° C., and a CrMo alloy base film is formed on a NiP-plated substrate subjected to TEX by DC magnetron sputtering.
Further, the magnetic characteristics of the magnetic recording medium on which the CoCrPt alloy magnetic film was formed were measured. At this time, the composition ratio of CrMo was controlled by embedding a Mo chip in a Cr target. As a result, it was found that the CoCrPt alloy magnetic film using CrMo as the underlayer has improved Hc as compared with the case of using conventional Cr as the underlayer. Such an effect was recognized under the condition of Mo 5 at% or more and 40 at% or less. Moreover, the same effect was recognized even when Mo was replaced with W.

Further, in order to maintain Hc at a high value for in-plane magnetic recording in a reproducible manner, it is desirable to provide a nonmagnetic metal underlayer made of a CrMo alloy or a CrW alloy with a thickness of 100 to 3000 Å.

Further, the surface of the magnetic recording medium has 50 to 50
By forming a 500 Å non-magnetic coating film, durability and corrosion resistance can be improved.

[0009]

EXAMPLES Examples of the present invention will be shown below.

[Manufacturing Method]: ILC-3 manufactured by Nichiden Anelva
108 was used to perform sputtering by a DC magnetron sputtering method. A NiP plated Al plate (95 mmφ) was used as the non-magnetic substrate layer. The target was Cr alloy / Co ₇₅ Cr ₁₃ Pt ₁₂ alloy / C, and experiments were conducted by burying Mo and W on the Cr target. The composition ratio of the Cr alloy was controlled by the number of pellets.

Next, the magnetostatic characteristics and the recording / reproducing characteristics of the magnetic recording medium manufactured by the above manufacturing method were examined. The static magnetic characteristics were measured using a vibration type magnetic characteristic device (VSM), and the recording / reproducing characteristics were measured using a MIG head with a gap length of 0.4 μm, a track width of 10 μm and a flying height of 0.1 μm, and a recording density of 36 KFCI ( 20m radius
m) and the respective results are shown in Table 1.

[0012]

[Table 1]

From Table 1 above, it was confirmed that in Examples 1 to 5 of the present invention, high coercive force and low noise were obtained.

[0014]

As described above, the magnetic recording medium of the present invention can obtain a magnetic disk, a magnetic drum, a magnetic tape or the like which satisfies both the characteristics of high coercive force and low noise and enables high density recording. Is something that can be done.

Claims (2)

[Claims] 1. A magnetic recording medium comprising a non-magnetic metal underlayer, a magnetic layer and a protective layer provided on a non-magnetic substrate layer, wherein the non-magnetic metal underlayer is Cr 95-60 at% and one of Mo and W. A magnetic recording medium, which is a thin film medium having an alloy composition of 5 to 40 at% of at least one species. 2. The thickness of the Cr alloy of the non-magnetic metal underlayer is 1
The magnetic recording medium according to claim 1, wherein the magnetic recording medium has a size of 00 to 3000Å.