JPH02108240A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain good C/N even if high-density recording is executed with an alloy head by forming a thin ferromagnetic metallic film by a cluster ion beam vapor deposition method on a moving high-polymer film and further passing the film through the plasma formed by an org. gas as a discharge das. CONSTITUTION:An unwinding shaft 3 and a receiving shaft 4 are provided in a vacuum vessel 10 having a vacuum evacuation system 11 in the upper part and the high-polymer film 1 consisting of polyethlene terephthalate, polyphenylene sulfide, etc., is moved along the outer periphery of a cylindrical can 2. A crucible 5 which houses a material 6 for vapor deposition, such as Co-Cr or Co-Ni, therein and is wound with a high-frequency induction coil 7 on the outer periphery is disposed to the lower side thereof. A high-frequency blow discharge electrode 8 having an insulated introducing terminal 9 at the end is positioned between the crucible and the can 2. The device is constituted in such a manner and the material 6 for vapor deposition is diagonally deposited by evaporation at a min. incident angle of 40 deg. on the film 1. Graphite is used as a target at this time and a diamond-like hard carbon film is formed under the conditions of Ar+H2=1:3.6, 13.56MHz.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method of manufacturing a magnetic recording medium having a magnetic recording layer made of a ferromagnetic metal thin film suitable for high-density magnetic recording.

Conventional technology In order to realize high-density recording, a G o -N i -0 obliquely deposited film is required. IEEE TRANSAC
TIONSON MAGNETIC3) Vo4 MAG
-20, P, P, 824-82θ (1984)), C
o -Cr-Nb perpendicular magnetization film [JP-A-61-77128
The best method is to combine a magnetic recording medium with a magnetic recording layer made of a ferromagnetic metal thin film, such as the one disclosed in [No.
Since there is a need for a structure that satisfies the durability required for magnetic recording media, various improvements are currently being studied. These are plasma polymerized films (Japanese Patent Laid-Open No. 61-151
No. 837), oxide film, nitride film (JP-A-61-151)
No. 830, JP-A No. 61-131231), combination of hard carbon film and lubricant layer (JP-A No. 61-12
Co-Cr, Co-Ti, Co-Ta, etc.
, Co-Ni, Co-N i -0, Co-N
A protective layer,
Since the film forms a lubricating layer and cannot be made too thick due to spacing loss, the contact area is reduced by using a base that forms fine irregularities on the ferromagnetic metal thin film. Attempts have been made to improve the results [JP-A-59-207422, JP-A-59-12163]
Publication No. 1].

Problems to be Solved by the Invention However, in the case where the protective lubricant layer is applied in a separate process as described above, not only is it desired to improve the uniformity, but also the narrow track of the alloy head is desired. Improvements have been desired since it is not possible to obtain a good envelope sufficiently to cope with the current situation. The present invention has been made in view of the above-mentioned circumstances, and provides a method for manufacturing a magnetic recording medium that has both a narrow track C/N and durability in an alloy head.

Means for Solving the Problems In order to solve the above-mentioned problems, the method for manufacturing a magnetic recording medium of the present invention uses an organic gas when forming a ferromagnetic metal thin film on a moving polymer film by cluster ion beam evaporation. This is designed to allow plasma, which is a discharge gas, to pass through.

Function: Since the method for manufacturing a magnetic recording medium of the present invention works so that the non-magnetic material covers the ferromagnetic metal fine particle crystals, unlike the conventional case where a protective layer is laminated on a ferromagnetic metal thin film, durability is improved. In addition to the improved filling ratio and good crystallinity, it is possible to manufacture a magnetic recording medium with a large squareness ratio, a large amount of saturation magnetic flux, and an improved C/N ratio.

Furthermore, even if it is deposited on a polymer film in an ionized state, it forms a cluster and has an extremely small charge-to-mass ratio, which also has the effect of preventing an increase in noise due to electrostatic variations.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The figure is a configuration diagram of the main parts of a winding vapor deposition apparatus used to carry out the present invention. In the figure, 1 is a polymer film made of polyethylene terephthalate, polyphenylene sulfide, polyether ether ketone, polyimide, etc., and if necessary, a subbing layer, a base layer, and a soft magnetic layer may be provided in advance. 2 is a cylindrical can, which is insulated and constructed so that a potential can be applied to it. 3 is an unwinding shaft, 4 is a winding υ axis, 5 is a crucible, and e is Co-Cr, Co-Ni, C
7 is a high frequency induction coil, 8 is a high frequency glow discharge electrode, which preferably also serves as a nozzle for introducing organic gas.

9 is an insulation introduction terminal, 1o is a vacuum container, and 11 is a vacuum exhaust system. In the device shown in the figure, the diameter of the cylindrical can is 5ocrn, the insulation resistance is 800 (MΩ) at 1500V, and a Z ro2 with a 0.1H hole 25crn directly below the can.
A crucible is placed on the 2-turn high frequency glow discharge electrode.
The test was carried out by arranging 20 gas introduction holes of 5φ.

Co-Cr (CoNia 92wt
%) by electron beam evaporation to form a 0.14 μm obliquely deposited film of 4
It is formed at a vacuum degree of
, i (Torr)Ar; H2=i: s, a
, 13.58 (MHz).

A magnetic tape having a width of 8 mm was prepared by depositing 150 diamond-like hard carbon films by sputter deposition under the conditions of 940 (W) and then depositing stearic acid by vacuum evaporation for 40 people, and prepared this as a comparative example. The example uses the same film with a minimum incident angle of 30 degrees and Co-Cr(Co: 79.2 w
t%) by cluster ion beam evaporation to a thickness of 0.14 μm.
A thin film was formed. At that time, CH4 gas was added to 0.2 (l
/IJJI), 13.56 (MHz),
A high frequency glow of 520 (W) was generated, and a negative voltage of 500 μ was applied to the can.

A magnetic tape having a width of 8 mm was similarly manufactured by disposing a diamond-like hard carbon thin film on a 0.14 μm thin film by 90 people and a stearic acid film by 40 people (Example A).

In addition, as an organic gas, hexamethylcyclotrisilazane was introduced at a rate of 0.121/am, and a rate of 13.56 (MHz
).

Generates a high frequency glow of 41o (W) and
An 8 mm tape was manufactured under the same conditions as Example A except that a negative voltage of 60 (V) was applied (Example B).

Next, allyl alcohol was added as an organic gas to O, Oa (17
m), Cannon gas 0.02 (71!/III way)
It was manufactured under the same conditions as Example A, except that a high-frequency glow of 800 (W) at 2 o O (KHz) was generated, and a negative voltage of 710 (V) was applied to the can (Example C). ).

Using these tapes, the track pitch was 7 μm.

High-density magnetic recording at a recording wavelength of 0.47 μm was performed using an amorphous head, and Cc was compared. Comparative example o(
dB), Example A is +2.9 (dB).

Example B is +2.8 (dB), Example C is +3.3
(dB).

In addition, when we prepared 5 rolls of each tape and compared the C/N, the comparative example had an average value of 0 (dB) and 2.1 (
dB) to +0.9 (dB), but in the example, A had an average value of 2.9 (dB), 2.65 to 2.9
9 (dB), B average value 2.8 (dB), 2.64
~2.91 (dB), C is average value 3.3 (dB),
3.06 to 3.41 (dB), respectively, indicating that the noise has little local unevenness.

Also, each tape was 40'C88%RH, 5.7ppm.
As a result of leaving it in a 5o2 gas environment for one month and comparing the change in slope before and after, the comparison example showed -6.7 (dB) compared to the initial value.
In contrast, in the example, A decreased by -1, 1 (
dB), B is -0,2(dB), C is -0
, 7 (dB), which was good.

In addition, even in the stealth state, the comparative example was 33 minutes, and the example A.

The durability of B and C was also confirmed, with the output only decreasing by 1 (dB) from the initial output after 36 minutes, 34 minutes, and 38 minutes, respectively.

Similar improvements could be made with Co-Ni and Co-Nd other than those mentioned above, but for co-Ni, by mixing oxygen with organic gas at a flow rate of 10% to 26% of the organic gas. It was found that the improvement was better than using organic gas alone.

Under optimal conditions, the output hardly changes and the noise is about 1 (dB)
Improved.

Effects of the Invention As described above, according to the present invention, it is possible to provide a good C/N ratio when high-density recording is performed with an alloy head.
This has the excellent effect of making it possible to manufacture a magnetic recording medium that has both durability.

[Brief explanation of drawings]

The figure is a configuration diagram of main parts of a cluster ion beam evaporation apparatus used to implement the present invention. DESCRIPTION OF SYMBOLS 1... Polymer film, 6... Evaporation source container, 6... Evaporation material, 8... High frequency glow discharge electrode.

Claims (1)

[Claims] A method for producing a magnetic recording medium, which comprises passing plasma using an organic gas as a discharge gas when forming a ferromagnetic metal thin film on a moving polymer film by cluster ion beam evaporation.