JPS61104431A - Production of vertical recording magnetic medium - Google Patents

Abstract

PURPOSE:To obtain the intra-surface magnetization anisotropy of a 'Permal loy(R)' film by blanking a double layer film medium of lines of magnetic force into a circle by means of magnets arranged specially, a yoke and a mask when the 'Permalloy(R)' film is formed on a nonmagnetic substrate. CONSTITUTION:The steam supplied from an evaporation source 8 of a crucible 7 is vapor deposited onto a nonmagnetic substrate 9. A 'Permalloy(R)' film is continuously vapor-deposited on the substrate 9. Then the tangent direction of the line 12 of magnetic force is equal to the magnetization easy axis together with the normal line direction equal to the magnetization difficult axis respective ly for the 'Permalloy(R)' film. In other words, the magnetic anisotropy can be freely controlled with the vapor deposition of the 'Permalloy(R)' film using magnets 4. Thus a vertically magnetized film is formed on the substrate 9 containing a 'Permalloy(R)' film for production of a recording medium. This recording medium is blanked into a circle for production a disk medium 13. Thus it is possible to obtain a disk vertical recording magnetic medium having the anisotropy of the magnetization difficult axis to the circumferencial direction of the medium 13.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method of manufacturing a magnetic recording medium for perpendicular recording, which has excellent characteristics for high-density recording.

(Constitution of Conventional Example and its Problems) Generally, the perpendicular magnetic recording method is well known as a recording method that is effective in providing excellent short wavelength recording characteristics. Since this utilizes residual magnetization in a direction perpendicular to the film surface of the recording medium, a film in which residual magnetization remains in a direction substantially perpendicular to the film surface of the recording medium, that is, a perpendicular magnetization film is required. The perpendicular magnetization film is C
The Co-Cr perpendicularly magnetized film, whose main components are O and Cr, has excellent properties. The latter method has an extremely high film deposition rate and is therefore suitable for mass production.

As shown in the cross section of FIG. 1, the single-layer Co-Cr perpendicular magnetization film 1 as described above is a so-called two-layer film medium in which a Tsukuumalloy film 3 is provided between it and a substrate 2 made of a non-magnetic material. It is known that recording efficiency and reproduction output can be improved by adopting a structure called .
Both the recording efficiency and the reproduction efficiency are improved by about 20 dB.0 In order to further improve the characteristics, it is necessary to increase the initial permeability of the Tsukuumalloy film 3 in the above-mentioned two-layer film medium. It is possible to add in-plane magnetization anisotropy.

The method for imparting in-plane magnetization anisotropy is to continuously deposit a gummalloy film on a long non-magnetic substrate in a magnetic field. It is sufficient to apply a single magnetic field in the width direction of the non-magnetic substrate, but in the case of manufacturing a disk-shaped perpendicular magnetic recording medium, applying a magnetic field in a single direction will cause the circle of the finished disk-shaped medium to The envelope of the recording/reproduction output in the circumferential direction has a modulation of several tens of degrees, as shown in the reproduction output waveform in FIG. Note that modulation refers to the maximum and minimum values of the playback output, respectively.
, B, (A-B)/(A+B)Xi OO(
%), and generally a value of 10% or less is required for characteristics.

That is, in the manufacturing method of disk-shaped perpendicular recording media, the method of imparting in-plane magnetization anisotropy similar to that for tape-shaped recording media cannot be applied, and the development of a new method has been desired.

(Object of the Invention) In view of the above-mentioned circumstances, the present invention aims to improve the recording and reproducing characteristics of a disk-shaped perpendicular magnetic recording medium having a two-layer film structure, particularly by in-plane magnetization of an /IP-Malloy film. The present invention provides a manufacturing method that focuses on imparting anisotropy.

(Structure of the Invention) In order to achieve the above object, the present invention, when forming a permalloy film on a non-magnetic substrate, uses specially arranged magnets, a yoke, and a mask so that lines of magnetic force are directed in the direction of substrate movement at the center of the mask. A double-layered film medium is formed by forming a perpendicular magnetization film on the end portions in the width direction, and then punching out a circular shape so that the circumferential direction is almost the direction in which magnetization is difficult. be.

(Explanation of Examples) The present invention will be explained below using examples.

FIG. 3 is a schematic side view of the continuous vacuum evaporation apparatus.

4 is a magnet, 5 is a yoke, 6 is a mask, and Rutsu i! 7
The vapor from the evaporation source 8 is passed between the magnets 4 and deposited on the nonmagnetic substrate 9. In addition, 10 in the figure is a capstan, 11
is a frame of 90 rolls of non-magnetic substrate.

The present invention uses such a continuous vacuum deposition apparatus to deposit a permalloy film forming a two-layer film medium.

4(a) and 4(b) are plan views showing the arrangement of the magnet 4, yoke 5, and mask 6 of FIG. 3, respectively, used for carrying out the present invention, and the arrow A shown therein indicates a non-magnetic substrate. 9
, and 6' is a mask hole. (b
) The figure shows an arrangement configuration that has three times the effect as the configuration shown in the figures (,), and in both cases, the same effect can be obtained even if the direction of the N-8 magnetic pole of the magnet is changed.

Figure 5 shows magnetic field lines 1 generated in the configuration shown in Figure 4(a).
2, and FIG. 6 shows the state in which the lines of magnetic force 12 are at the mask hole 6', and the lines of magnetic force 12 are at the center of the mask hole 6' in the width direction, and the movement of the non-magnetic substrate 9 is shown in FIG. It is almost parallel to arrow A indicating the direction, and almost perpendicular at both ends. Therefore, if a gummalloy film is continuously vacuum-deposited on the non-magnetic substrate 9 using the arrangement shown in FIG. 2, the tangential direction of the magnetic lines of force 12 becomes the axis of easy magnetization, and The normal direction becomes the direction of the hard magnetization axis i
A 4-Malloy film can be formed on the nonmagnetic substrate 9.

FIG. 7 shows the B-H curve when the Gumalloy film was formed as described above, and the (■) diagram shows the case without the magnet 4 shown for comparison, and the nonmagnetic substrate 9. The curve characteristics remain unchanged in the moving direction and the width direction. be). However, the magnetization anisotropy differs depending on the Fe-Ni composition ratio of the permalloy film, and the in-plane magnetization and orientation of the permalloy film can be freely controlled in the production of magnetic recording media for perpendicular recording. It is necessary and cannot be done without a magnet.

(n) Figure shows the case where a magnet 4 is provided. When the magnet 4 is provided, the moving direction is the easy magnetization direction in the center part of the non-magnetic substrate as shown in (a), and the direction in which magnetization is easy at both ends (b). As shown, the width direction is the direction of easy magnetization. That is, in the vapor deposition of the permalloy film using the magnet 4 as described above, the magnetization anisotropy can be freely controlled.

If a recording medium manufactured by forming a Co--Cr perpendicularly magnetized film on a non-magnetic substrate on which a permalloy film is formed as described above is punched out into a circular shape as shown in FIG. A disk-shaped magnetic recording medium for perpendicular recording, which has anisotropy of the hard axis of magnetization in the circumferential direction and has recording and reproducing characteristics superior to conventional two-layer film media, can be obtained. In addition, (a
) and (b) correspond to the arrangement of magnets, etc. in (a) and (b) of Figure 4, and three circular media can be obtained by punching as shown in (b). .

A specific example is shown below.

With the configuration shown in Figure 4 (,), the dimensions of the mask hole 6' are 40wX.
140 m, and the magnet 4 was a 10 m x 10 m x 20 x Sn-Co magnet magnetized in the longitudinal direction.
The yoke 5 was formed using soft iron of 40w x 140w x 10m. Note that the polarity of the magnet 4 was as shown in FIG. At that time, the strength of the magnetic field generated by the magnet 4 is 1
It was about 00-3000e. A permalloy film having a thickness of 1,000 to 5,000 µm was deposited by continuous vacuum evaporation using a polyimide heat-resistant polymer film having a thickness of 30 µm as the nonmagnetic substrate '9, constituting such a magnetic field part. As a result, the above-mentioned figure 7 (10 twists - H
A curve was obtained.

Furthermore, Co - Cr was continuously vacuum-deposited on the permalloy film, and a disk-shaped medium 13 was punched out as shown in FIG. Compared to conventional media in which the easy magnetization direction and the difficult magnetization direction were not taken into account or the directions could not be controlled, the characteristics were improved by 3 dBB10. Also,
The modulation in the circumferential direction of the medium, which was conventionally several tens of degrees, satisfies the generally required value of 10% or less.

(Effects of the Invention) As is clear from the detailed explanation above, the present invention provides a two-layer film medium in which a perpendicularly magnetized film is formed on a non-magnetic substrate via a permalloy film. This is a method for manufacturing perpendicular magnetic recording media that forcibly changes the in-plane magnetization anisotropy of the film in the width direction of the substrate, thereby obtaining properties that are even better than those obtained with a conventional two-layer film structure. Therefore, it can be of great benefit when used in high-density digital recording.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view illustrating a magnetic recording medium with a two-layer film structure.
Fig. 2 is a reproduction output waveform diagram explaining modulation, which is one of the characteristics of magnetic recording media, Fig. 3 is a side view showing the configuration of a continuous vacuum evaporation device, and Fig. 4 is a diagram of the magnet part, which is the main part of the present invention. A plan view showing the arrangement configuration, FIG. 5 is a plan view explaining the magnetic lines of force in the previous time, FIG. 6 is a plan view explaining the magnetic lines of force in the mask hole, FIG. 7 is a B-H, curve diagram, and FIG. FIG. 3 is a plan view showing punching when forming a disc-shaped medium. DESCRIPTION OF SYMBOLS 1... Co-Cr perpendicular magnetization film, 2... Substrate, 3...
...Permalloy film, 4...Magnet, 5...Yoke, 6
... Mask, 6'... Mask hole 1.7... Crucible, 8... Evaporation source, 9... Nonmagnetic substrate, 10... Capstan. Figure 1 Figure 4 (a) (b) Figure 5 Figure 6 Figure 7 Figure 8 (a)

Claims (2)

[Claims] (1) While applying a magnetic field using a vacuum evaporation device equipped with a magnet, a yoke, and a mask, a permalloy film is formed on a non-magnetic substrate so that the axis of easy magnetization is in the width direction of the non-magnetic substrate; 1. A method for manufacturing a magnetic recording medium for perpendicular recording, which comprises forming a two-layer recording medium by depositing a perpendicularly anisotropic magnetized film on its surface, and punching it into a disk shape. (2) A magnet and a mask are installed in the continuous vacuum deposition apparatus so that the axis of difficult magnetization of the permalloy film is formed in the direction in which the punched disk-shaped recording medium moves relative to the magnetic head during recording and reproduction. A method of manufacturing a magnetic recording medium for perpendicular recording according to claim (1), characterized in that a magnetic recording medium for perpendicular recording is arranged.