JPH01189030A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To speed up production by forming a thin ferromagnetic film of a Co-N or Fe-N system by plasma decomposition of metal dialkyl amide. CONSTITUTION:Vapor of the metal dialkyl amide is introduced through a gas introducing hole 6 into a vessel and plasma is induced by the high frequency impressed to a coil 7 from the outside to form the thin ferromagnetic film of the Co-N or Fe-N system as the resulted product of the decomposition reaction. The saturation magnetic density is optimized by increasing the power of the plasma to adequately change the ratio of the Co and the N or the Fe and the N and the uniaxial anisotropy is increased by directing a plasma gun diagonally to the high-polymer film 1. An increase in coercive force is attained as the vapor flow is active and the crystallinity is good.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of manufacturing a magnetic recording medium using a ferromagnetic thin film as a magnetic recording layer.

Conventional technology In recent years, there has been remarkable progress in increasing the density of magnetic recording.

There is a strong desire to put into practical use magnetic recording media in which a magnetic recording layer is a ferromagnetic metal thin film such as a -Ni-0 obliquely deposited film or a Co--Cr perpendicularly magnetized film. On the other hand, iron nitride thin films formed by ion-assisted vapor deposition have high coercive force and excellent weather resistance, and are therefore expected to be used as magnetic recording layers. [IEE Transaction on Magnetics (I
EEETRANS ACTIONS ON MAGNE
TIC3) vol.

See MAG-22, 591 (1986)].

Problems to be Solved by the Invention However, the formation rate of iron nitride thin films is slow in the so-called ion-assisted deposition method, in which oblique evaporation and ion irradiation are performed simultaneously, so studies have also been conducted, such as vertical evaporation and oblique ion irradiation. However, it has not been possible to increase the coercive force, and it has not been possible to obtain a high coercive force at high speeds, so improvements have been desired.

The present invention was made in view of the above circumstances, and
, or a method capable of manufacturing Fe--N based ferromagnetic thin films at high speed.

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 includes forming a Co-N or Fe-N based ferromagnetic thin film by plasma decomposition of a metal dialkylamide. This is what I did.

Effect: According to the above-described structure, the method for manufacturing a magnetic recording medium of the present invention can optimize the saturation magnetic flux density by appropriately changing the ratio of CO and N or Fe and N by increasing the plasma power. By pointing the plasma gun obliquely at the polymer film, it is also possible to increase the -axis anisotropy.
A high coercive force can be achieved by making the vapor flow active and having good crystallinity.

EXAMPLE Hereinafter, an example of the present invention will be described in detail with reference to the drawings. The figure is a block diagram of the main parts of a magnetic recording medium manufacturing apparatus used to carry out the manufacturing method of the present invention. In the figure, reference numeral 1 indicates a polymer film of polyethylene terephthalate, polyphenylene sarcoide, polyether imide, etc., which may be provided with an undercoat layer if necessary. 2 is a rotating support, 3 is an unwinding shaft, 4 is a winding shaft, 6 is a reaction tube, 6 is a gas introduction hole, 7 is an external high frequency coil, 8 is a DC acceleration electrode, 9 is a plasma flow, 1o is a The direct air container 11 is a vacuum evacuation system. It can be selected as appropriate whether to direct the plasma flow obliquely to the polymer film to form an in-plane magnetized film or to direct the plasma flow perpendicularly to the polymer film to form a so-called perpendicular magnetized film.

In the present invention, metal dialkylamide vapor is introduced through a gas introduction hole, plasma is induced by externally applied high frequency, and Co -N or Fe, - is produced as a decomposition reaction product.
Co (N He2
) 4. F e (N He2 ) 4 , Co
The starting material is a metal dialkylamide such as (N E t2)4°Fe(N-nBu2)4, and if necessary, Ar, He, H2, etc. may be added as a discharge gas. Examples of the present invention will be described in more detail below.

On a polyethylene terephthalate film with a thickness of 10 μm, 15 Eu2O3 particles with a diameter of 100 μm were added.
) Set the two rolls arranged on the unwinding shaft, and after evacuation to 2 x 10-6 (Torr) in advance,
F e (N E t 2 ) 4 to 0.9 l
/min while introducing 13.56 (MHz),
A high frequency of 1.3 (KW) was applied to generate plasma, and 3 sOcJ) was applied to the DC accelerating electrode, the rotating support was set at ground potential, the plasma was accelerated, and the central axis of the reaction tube was aligned with the polymer film. On the other hand, a 0.15 μm Fe-N film was formed at an incident angle of 46 degrees. This film has a saturation magnetic flux density of 5soo (G) and a coercive force of 890 (Oe
), the C/N was measured using 8mm video, and the brightness C/N was +2.7 (dB) compared to commercially available metal coated tape.
)i.

60"C85%RH After being left for 2 months, the C/N of the metal coated tape is -0, 5 to -0.7 (dB) compared to the initial stage.
/N was low at -1.8 to -2.4 (dB), but the stability was also good.

In addition, 0, which was manufactured under 45 o (V) DC acceleration under high frequency application conditions of 13.56 (MHz) 1.9 (KW),
The 15 μm Fe-N film has a saturation magnetic flux density e e o o
(G) With a coercive force of 1050 (Oe), the brightness C/N measured with an 8 mm video is +s, 9 with respect to the metal coated tape.
(dB), and the C/N after being left at 60°C and 85° RHS for 85 months was -0, 4 to -o, 5 (dB) compared to the initial C/N, whereas the C/N of the metal coated tape was against -3,3
It had decreased by ~-3.9 (dB).

In the above-mentioned shida film formation, the film feeding speed is 13-1F5 (m
/min), which is faster than the ion-assisted vapor deposition method, which has a speed of 2 to 2.6 (m/mit+) with approximately the same equipment scale.

In addition, a Co-N perpendicular magnetization film is manufactured, and the electromagnetic conversion characteristics, weather resistance, and high speed are improved using the high-frequency sputtering method.
As a result of a comparative study with an example in which a perpendicularly magnetized film was formed, it was found that since the film is hard and has good durability, the thickness of the protective film is less than 1/3 of that required for the Co-0r film, and the spacing loss is improved.
As a result, the /N was only about 0.5 (dB) lower, the weather resistance was the same, and the film speed was 7 to 12 times faster.

Effects of the Invention As described above, according to the present invention, F
An excellent effect is that a magnetic recording medium having an e-N or Co-N based ferromagnetic thin film as a magnetic recording layer can be manufactured at high speed.

[Brief explanation of the drawing]

The figure is a block diagram of the main parts of a magnetic recording medium manufacturing apparatus used to carry out the present invention. DESCRIPTION OF SYMBOLS 1... Polymer film, 5... Reaction tube, 7... External high frequency coil, 9... Plasma flow.

Claims (1)

[Claims] A method for manufacturing a magnetic recording medium, characterized in that a Co--N or Fe--N based ferromagnetic thin film is formed by plasma decomposition of a metal dialkylamide.