JPH02285506A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain the magnetic recording medium excellent in corrosion resistance and with the bit-shift reduced and the residual magnetization increased by forming the magnetic film with a specified alloy. CONSTITUTION:The magnetic film of a magnetic material is provided on the surface of the substrate of a nonmagnetic material through the base film of a nonmagnetic material. The magnetic film is formed with an alloy contg., in an atomic ratio, 5.0-15.0% Cr, 1.0-8.0% Ta, 0.5-5.0% C and/or P and the balance Co. As a result, information can be recorded and reproduced between the medium and a magnetic head, for example, and a magnetic recording medium excellent in corrosion resistance and with the bit-shift reduced and the residual magnetization increased is obtained.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a magnetic recording medium for recording and reproducing information between, for example, a magnetic head. It is related to recording media.

[Conventional technology]

Conventionally, a magnetic disk device has been used to record information on a magnetic recording medium or reproduce and output information recorded on the medium, or when performing the above recording and reproduction, a magnetic head and a magnetic recording medium are used. For example, 0.2 to 0.3
It is normal to maintain a micro gap of μm. Therefore, in order to prevent friction and wear caused by contact between the magnetic head and the magnetic recording medium, and/or damage caused by collision between the two, a floating RAD slider is used. That is, due to the relative speed of the magnetic herad slider with the surface of the magnetic recording medium.

It is configured to maintain a minute gap between the two by utilizing a hydrodynamic floating blade generated in the gap between the two. On the other hand, the specifications required for magnetic recording media in recent years have become progressively stricter, and not only do they require a high degree of recording per record, but they also require
A magnetic film with a small shift and a large residual magnetization is required.

[Problem to be solved by the invention]

The material forming the magnetic film is Co-Ni.
Alloys such as Pt, Co Ni Cr, etc. are used, but while the former has the advantage of high coercive force, it has a low S/N ratio and high noise, and also contains Pt, a noble metal, in one alloy. It has the disadvantage of being expensive because it contains

On the other hand, the latter is lower in cost than the former and can reduce noise, but has the disadvantage of being insufficient in terms of corrosion resistance, that is, a large rate of decrease in saturation magnetization due to environmental changes, and reliability. Furthermore, in recent years when performing high-density recording, there are many errors due to large bit shifts9.
For example, at an error rate of 10-9, it is about 28 ns, which is poor reliability. Furthermore, in order to ensure a predetermined coercive force, it is necessary to increase the thickness of the Cr film that is to be deposited on the substrate as an underlayer, which takes a long time to form to a predetermined thickness and reduces productivity. There is a problem in that it invites

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems existing in the prior art described above, and to provide a magnetic recording medium that is particularly excellent in corrosion resistance and can improve pitch 1-shift and residual magnetization characteristics.

(Means for solving the problem) In order to achieve the above object, in the present invention, a magnetic film made of a magnetic material is provided on the surface of a substrate made of a non-magnetic material with a base film made of a non-magnetic material interposed therebetween. In magnetic recording media, the magnetic film contains 5.0 to 15.0% Cr in atomic %.
Ta 1.0-8.0% C and/or PO15
It is formed of an alloy consisting of ~5.0% Co and the balance Co.

A technical method was adopted.

In the present invention, if the Cr content is less than 5.0 at %, the corrosion resistance decreases, that is, the rate of decrease in saturation magnetization due to changes in the environment is large, and the S/N ratio decreases, which is disadvantageous. On the other hand, if Cr exceeds 15.0 atomic %, this is not preferable because the residual magnetization decreases, leading to a decrease in output, and the S/N ratio also decreases.

Next, Ta contributes to improving the S/N ratio, but 1.0 at%
If the content is less than 8.0 atomic %, the effect cannot be expected, whereas if it exceeds 8.0 at %, the S/N ratio will decrease again, and the residual magnetization will also decrease, resulting in a decrease in output, which is not preferable.

Furthermore, by containing an appropriate amount of C and/or P,
It has the effect of improving focus shift. However, if it is less than 0.5 at%, the effect of bit shift 1~improvement is insufficient;
On the other hand, if the content exceeds 5.0 at %, it is not preferable because it not only increases the bit shift again but also reduces corrosion resistance and reduces the output due to a decrease in residual magnetization.

Note that the base film is preferably formed of Cr or a Cr alloy. In this case, the Cr alloy is Cr
-Mo, Cr-V, Cr-Mn, and other alloys can be used.

Further, it is preferable that the substrate be formed of aluminum or an aluminum-based alloy.

[For production]

With the above configuration, information can be recorded and reproduced with, for example, a magnetic head, and a magnetic recording medium with excellent corrosion resistance and excellent tip shift and residual magnetization performance can be obtained.

〔Example〕

The surface of the substrate made of aluminum alloy containing 4% by weight of magnesium was formed smooth by turning, and the outer diameter was 9.
The substrate had a diameter of 5 mm, an inner diameter of 25 mm, and a thickness of 1.27 mm. Next, a plating film made of NiP alloy is formed on the surface of this substrate to a thickness of 5 to 15 μm, and the plated film is formed to have a thickness of 5 to 15 μm. and
3top (hereinafter referred to as CSS) characteristics. The surface of the metal wood film deposited as described above is polished to a smooth surface, and is also textured to prevent adhesion to the magnetic head or slider. Next, after cleaning the substrate, a base film made of Cr, a magnetic film made of Co-Cr-1'a alloy, and a protective film made of C are sequentially laminated using, for example, a DC magnetron sputtering device. In this case, to form the base film, the sputtering chamber is
After evacuation to below 10-5 Torr, the substrate was heated at 200°C for 30 minutes, Ar gas was introduced to maintain the sputtering chamber at 5 mTorr, and the film was deposited under the following conditions: input power: 2000 W, deposition rate: 400 people/min. A film was formed to a thickness of 1000. Next, on this base film, apply C and/or as shown in the table below.
or co containing P, Cr, 5Ta3 (all numbers are atomic %
shows. A magnetic film made of an alloy (the same applies hereinafter) was formed to a thickness of 600 people in the same manner as described above under the conditions of input power of 2000 W and film formation rate of 1000 people/min. In this case C and /
Or to change the content of P, the content of C8
-Cr-Ta based target material may be used, but co
-c, -'P, C and/or I) targets having the area ratio of the content may be embedded in the target surface of the system.

The protective film was manufactured using an input power of 1000 W and a film formation rate of 80 people/
A film was formed on the magnetic film to a thickness of 300 ml under conditions of 300 min.

A liquid lubricant was applied to the surface of the magnetic recording medium produced as described above, and the medium was mounted in a 3.5 inφ disk drive and the focus shift and residual magnetization were measured. The results are also shown in the table. Na'! The magnetic head used for the f3 measurement was an Mn-Zn mini monolithic type (I rank width 20 μm), and the slider width was 61 [171 m].
, cymbal spring pressure 9.5 gf, flying height at a radius of 24 mm 0.2 μm, rotation speed of magnetic recording medium 2
Measured under the conditions of 400 r, p, m.

(Margin below) As is clear from the table, it is recognized that the inclusion of C and/or P reduces the focus shift. That is, No, 1.2, 8. In No. 14, the content of C and/or P is O or a small amount, so the value is similar to that of the conventional material, and no improvement in bit shift is observed. On the other hand, in No. 7, 1318, the content of C and/or P is too high, which not only results in a negative bit shift value, but also reduces the residual magnetization value, resulting in a decrease in output. It shows. On the other hand, No, 3～
It can be seen that in Nos. 6, 9 to 12 and Nos. 15 to 17, the bit shifting values also maintain predetermined values.

In this example, Cr is used as the material for forming the magnetic film.
COCr containing 12.5% and 3.0% 'Fa
Although the case where a -Ta alloy is used has been described, the present invention is not limited thereto, and the same effect can be obtained even if an alloy having an Itogi composition of 5 to 15% Cr, 1 to 8% Ta, and Co is used. In addition, as a material for forming the base film, not only Cr but also Cr such as Cr-Mo, CrV, Cr-Mn, etc.
It may be an r alloy. Furthermore, the material for forming the substrate is not limited to an aluminum-based alloy containing magnesium, but may also be aluminum, other metal materials, or non-metal materials. Furthermore, the means for processing the substrate is not limited to only turning, but may also be other methods such as grinding. Note that the Ar gas pressure in the sputtering chamber can be arbitrarily selected within the range of 2 to 30 mTorr.

〔Effect of the invention〕

Since the present invention has the structure and operation as described above,
This has the advantage that it is possible to obtain a magnetic recording medium that has excellent corrosion resistance, small bit shift, and large residual magnetization.

Claims (3)

[Claims] (1) In a magnetic recording medium in which a magnetic film made of a magnetic material is provided on the surface of a substrate made of a non-magnetic material with an underlying film made of a non-magnetic material interposed therebetween, the magnetic film has a Cr5.
15.0% of Ta, 1.0 to 8.0% of Ta, 0.5 to 5.0% of C and/or P, and the balance Co. (2) The magnetic recording medium according to claim (1), wherein the base film is formed of Cr or a Cr alloy. (3) The magnetic recording medium according to claim (1) or (2), wherein the substrate is formed of aluminum or an aluminum-based alloy.