JPS62298917A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve the running durability under high humidity of a magnetic recording medium by providing an intermediate layer contg. at least one kind selected from specific metals and the oxides thereof and protective layer selected from specific compds. respectively by a vacuum forming method for thin films on a thin film. CONSTITUTION:The intermediate layer contg. at least one kind selected from Al, V, Cr, Mn, Si, Nb, Mo, Ta, W and the oxides thereof and the protective layer selected from Mo-S, W-S, C, Si-O, Co-Cr-O, and Co-Ni-Cr-O are provided respectively by the vacuum forming methods for thin films no the thin film. The metal of the same kind may be used as a sputtering source in, for example, a sputtering device when the intermediate layer is constituted of the above- mentioned metal or oxide. Glow discharge may be impressed in an oxygen atmosphere after the formation of the above-mentioned metallic film if said layer is constituted of the above-mentioned oxides. The formation of said layer by sputtering, vapor depositing or ion plating in oxygen is equally satisfactory.

Description

Detailed Description of the Invention S. Detailed Description of the Invention [Industrial Application Field] The present invention relates to a magnetic recording medium having a Φ-type thin film as an s-type layer, and in particular, the present invention provides a magnetic recording medium that has running durability even under high humidity conditions. [Prior art] In recent years, a perpendicular S-magnetization recording system using a magnetic recording medium having an S-easy axis in a direction perpendicular to the film surface of the recording medium has been proposed. There is. In this vertical S recording method, the anti-S field in the recording medium decreases as the recording density increases, so excellent reproduction output can be obtained and it is essentially a method suitable for high-density recording.

In order to carry out the magnetic coupling of such a perpendicular magnetization recording method, a metal thin film type magnetic recording medium having an axis of easy magnetization in a direction perpendicular to the film surface of the recording medium is required. Such metal thin film magnetic recording media can be produced by vapor deposition, sputtering, ion blating, etc. (hereinafter referred to as In addition, in order to improve the recording and reproducing efficiency during perpendicular S-ratio recording and reproducing, a method for forming a thin film under the perpendicular magnetic recording layer made of the above-mentioned Co-Cr alloy film is used. A so-called two-layer perpendicular magnetic recording medium is known, in which a high magnetic permeability layer made of a soft magnetic material, for example, a permalloy (Ni-Fe alloy) film is provided as an underlayer.

However, such metal thin film magnetic recording media have a problem of poor running durability and abrasion resistance.

As a method to prevent such defects, it has been proposed to provide a protective layer made of thermoplastic resin or thermosetting resin on the surface of the magnetic layer, but the thickness of the protective layer is limited due to spacing loss between the head and the magnetic layer. Since there is a restriction that it cannot be made large, sufficient effects cannot be obtained.

[Problem that the invention seeks to solve]

As a protective layer for a magnetic recording medium, it has been proposed to provide a K or carbon-based protective layer by vapor deposition in order to improve the abrasion resistance of the mother plating layer (Japanese Patent Publication No. 33521/1983).

When such a carbon-based protective layer and the above-mentioned vacuum thin film formation method were applied to a metal thin film type magnetic recording medium, the running durability under normal humidity improved, but when stored under high humidity or high humidity The running durability has deteriorated significantly when running under low conditions. For example, under high humidity conditions of around 80% RH, the adhesion of the protective layer deteriorates, resulting in peeling and film falling, and in extreme cases, running I had no choice but to stop.

[Manual steps to solve the problem]

The present inventors have discovered that the above metal thin film type magnetic recording medium is deposited by vapor deposition,
As a result of repeated studies on the adhesion between the magnetic layer and the protective layer under high humidity when provided with a carbon-based surface Fi-retaining layer, it was found that AQ, V, Cr, Mn.
, Si + Nb , Mo , Ta , W and their oxides by forming an intermediate layer using a vacuum thin film forming method such as sputtering or ion brazing, which significantly improves the adhesion. However, it has been found that the running durability of a magnetic recording medium under high humidity can be improved, and the present invention has been achieved.

That is, the present invention provides a magnetic recording medium having a ferromagnetic metal thin film mainly composed of 1cco on a non-magnetic support.
, an intermediate layer comprising at least one layer selected from Ta, W, and oxides thereof, and Mo-S.

W-8, C, Si-O, Co-Cr-O, and Co
The present invention is a magnetic recording medium characterized in that protective layers selected from -Ni-Cr-0 are each provided by a vacuum thin film formation method.

The present invention will be explained in detail below.

The thin-film magnetic recording medium of the present invention consists of a non-magnetic support and a magnetic layer, an intermediate layer and a protective layer each provided on the non-magnetic support by a vacuum thin film forming method.

The magnetic layer may be made of a single layer of a thin ferromagnetic metal film mainly composed of Co, such as Co-Cr, but in the perpendicular magnetization method, a soft magnetic film made of a malloy alloy or the like is used as the lower layer, and the perpendicular The film-like support used in the present invention, which can be formed into a multilayer structure with a magnetized film as the top layer, is polyethylene terephthalate (PET), limide, polyamide, ? It can be applied to polymeric materials such as rifhenylene sarcoite, polyether sulfone, and polysulfone, but among these, polyimide, which has particularly excellent heat resistance, is preferred. The present invention can also be applied to a support having an underlayer. Aluminum, silicon, glass, etc. can also be used as the support.

In addition, the support is previously held in a vacuum, heat treated, or subjected to pretreatment such as glow discharge treatment,
It is desirable to reduce the emission of impurity gases from the surface and interior of the support.

Materials for the soft magnetic film include Ni-Fe and Ni-F.
e-Mo, N1-F@-Mo-Cu, etc.
−q.

alloy, Fe, Fe-u-3i, Fe-Ni-0
゜Fe −T i +Ni−Fe−Cn−Cr −Mn
, Fe-8i-B, Fe-B-C, Fe-
AJ Co -V-F@, C.

-Ta, Co-Zr, co-Nb-Zr, Co-
Ti.

Co-N, b-Ta, Co-Ni-Zr, Fs-
Ni-P.

Alloys such as Fe-P and Fe-Co-Zr are used.

The film thickness needs to be able to suppress the precipitation of oligomers and the release of impurity gas from the film support, and is 0.
．． The thickness is selected to be about 0.03 to 5 microns.

In order to obtain good perpendicular magnetization recording male characteristics, 01 to 1
Particularly desirable is a diameter of about microns.

The magnetic layer is Co-Cr, Co-Ni, Co-Ni-Cr
.

Co-Fe-Cr, ('o-cr-Ta +Co
-Cr -W+Co -Cr-Ma, Co -Cr
- It consists of one or more layers of strong-temperature thin film mainly composed of Co such as -V.

The film thickness is selected to be about 0.03 to 5 microns, but preferably about 0.05 to 1 micron.

As the film forming means, vapor deposition, sputtering, etc. are used, but it is preferable to use a so-called continuous sputtering method having a plurality of high-speed sputtering sources arranged around a plurality of cylindrical cans or a so-called in-line sputtering method.

Various high speed ivy sources can be used as the ivy source.

The present invention provides A! in the magnetic layer formed as described above. , V.

Cr, Mn + S l + Nb + Mo, Ta +
An intermediate layer containing at least one selected from W and oxides thereof is provided. The intermediate layer may be provided by the above-mentioned slanting method, or may be provided by vapor deposition, ion spraying, or the like. The thickness of the intermediate layer is about 10 to 100X.

When the intermediate layer is composed of the above-mentioned metal or its oxide, the same kind of metal may be used as a spore source in the above-mentioned sintering device, and when it is composed of the above-mentioned oxide, After formation with the above metal film, glow discharge may be applied in an oxygen atmosphere, or
The formation of the intermediate layer and the formation of the protective layer to be described later may be performed continuously in the same apparatus as the formation of the mother layer, or may be performed in separate apparatuses. You can also do this by

The protective layer of the present invention is Mo-8, W-8, C, Si-0
Or the main component is Co-Cr-0. Of these, C
It is particularly preferable to have as a main component.

The protective layer of the present invention is formed on the intermediate layer by a vacuum thin film forming method such as vapor deposition or zettering using the above substance as an evaporation source or a sputtering source. The thickness of the protective layer is 50-5
Approximately 00X is preferable.

For example, the sizing device and conditions for these intermediate layers and protective layers may be selected in accordance with the case where the above-mentioned mother layer is provided.

In the present invention, the magnetic layer, intermediate layer and protective tube as described above may be provided on only one side of the support, or may be provided on both sides.

Next, one aspect of manufacturing the perpendicular boron type magnetic recording medium of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a schematic diagram showing an example of a double-sided continuous sputtering device, for example, a roll-shaped polyimide film delivery IIv
11, and is wound up by the winder @5 via an intermediate roller and cylindrical cans 3 and 4 installed in the sputtering chamber 2.

The vacuum chamber includes the delivery chamber 6, suction chamber 2, and winding chamber 7-3.
Each chamber is divided by a partition wall, and each chamber is evacuated by exhaust systems 8, 9, 10, and 11, respectively.

In the sputtering chamber 2, a target 12 made of Co--Cr, a target 13 made of Cr, and a target 14 made of C, for example, are installed in a cylindrical can S, and a Co--Cr target 15, a Cr target 16, And the C target 17 is left facing the cylindrical can 4.

After the sputtering chamber was evacuated to a pressure of I x 10-'' torr or less, Ar gas was introduced from the gas introduction thread 16 and
X maintained at 10” torr In this state,
Target 12 is placed on one side of the running polyimide film.
Sputtering is performed using the target as a sputter cathode to first form a Co--Cr film, and then a Cr film and then a C film are formed using the targets 13 and 14 as sputter cathodes. Furthermore, targets 15116 and 17 were used in the same order as above on the opposite side of the support.

-Cr film After providing the Cr film and the C film by sputtering, the film is wound onto the winding shaft 5.

When using Cr-0 as the intermediate layer, for example, a thin layer of Cr is provided on the mother layer and then glow discharge is applied in an oxygen atmosphere (0210-1 to 10-3 torr).

This is merely an example of manufacturing the magnetic recording medium of the present invention, and various modifications are possible.

〔Example〕

Using the apparatus shown in FIG. 1, three kinds of magnetic recording media having the following configurations were prepared, each having four pieces f''L.

Note that the Cr-Q intermediate layer was formed by sputtering Cr in an oxygen atmosphere of 10<-2 >Torr.

Each of the perpendicular magnetization media thus produced was cut into a 3.5-inch disk and assembled into a commercially available jacket to make a floppy disk.

After storing the above floppy disk in an atmosphere of 50°C and 80% RH for one week, recording was performed at 25°C with a commercially available FD drive, and then 600r, p, m
, and while monitoring the playback signal, the robot was rotated, and the number of passes until it became unable to run was measured. (maximum 1
The test was canceled at 0,000,000 zos).

The results obtained are shown in Figure 2.

〔Effect of the invention〕

As is clear from the results in Figure 2, the comparative sample (Sample C) with a protective layer without an intermediate layer had varying running durability from 10,000 passes to 10,000,000 passes, and had poor reproducibility. .

On the other hand, in the case of the present invention, the travel/cess is 1
It can be seen that it is possible to manufacture magnetic recording media (samples A and B) with excellent durability (samples A and B) with good reproducibility, with a durability of close to 0 million passes.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of an apparatus for manufacturing the magnetic recording medium of the present invention, and FIG. 2 is a diagram showing the results of a running path test in the example. 2... Spatter X, 3.4... Can, 12, 13
゜14...Target for sputtering on one side, 15゜16.17...Target for sputtering on the other side Patent attorney (st07) Kiyotaka Sasaki, (and 2 others) Fig. 1 Fig. 2

Claims (1)

[Claims] 1) In a magnetic recording medium having a ferromagnetic metal thin film mainly composed of Co on a nonmagnetic support, Al,
An intermediate layer containing at least one selected from V, Cr, Mn, Si, Nb, Mo, Ta, W and oxides thereof, and Mo-S, W-S, C, Si-O, Co-Cr -O,
A magnetic recording medium, wherein a protective layer selected from Co-Ni-Cr-O and Co-Ni-Cr-O is provided by a vacuum thin film forming method.