JPS61243942A - Manufacture of vertical magnetic recording medium - Google Patents

Abstract

PURPOSE:To manufacture a double layer vertical magnetic recording medium having a soft magnetic lined layer which is made isotropic by applying a magnetic field in the direction being roughly vertically to the film surface of a long-sized substrate, in the vicinity of the part where the soft magnetic lined layer is formed. CONSTITUTION:The long-sized non-magnetic substrate 1 runs along the peripheral surface of a cylindrical can 2 and on its way, the vapor-deposited film of a soft magnetic material flying from an evaporation source 5 through the gap of a shielding plate 6 is formed on the surface of the substrate 1. Also, a soft magnetic material target is placed in the evaporation source 5 and sputtered by the ion of Ar(1), etc. In this state, by conducting current to a coil 7 which is placed on the shielding plate 6, a magnetic field is applied in the direction being roughly vertical to the film surface of the substrate 1 in the vicinity of the part where the soft magnetic lined layer is formed. In this way, a double layer vertical magnetic recording medium containing the soft magnetic lined layer which is made isotropic is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for manufacturing a perpendicular magnetic recording medium having excellent high-density recording characteristics, particularly a double-layer perpendicular magnetic recording medium.

2. Description of the Related Art A perpendicular magnetic recording method is known as a magnetic recording method with excellent short wavelength recording characteristics. This method requires a perpendicular magnetic recording medium whose axis of easy magnetization is approximately perpendicular to the film surface of the medium. When a signal is recorded on such a medium, the residual magnetization is oriented in a direction substantially perpendicular to the film surface of the medium, and therefore, the shorter the wavelength of the signal, the smaller the demagnetizing field within the medium, and a better reproduction output can be obtained.

Among these, a structure called a so-called two-layer perpendicular magnetic recording medium (hereinafter abbreviated as a two-layer film medium) in which a soft magnetic underlayer is provided between this perpendicular anisotropic film and a substrate made of a non-magnetic material is adopted. It is known that recording efficiency and reproduction output can be improved by this method. In particular, when recording and reproducing using a known auxiliary pole excitation type vertical head, the recording efficiency is approximately 20 d.
B is improved, and the reproduction output is improved by about 20 dB.

Problems to be Solved by the Invention In the above two-layer m-medium, the magnetic properties of the soft magnetic underlayer have a large influence on its recording and reproducing efficiency. Figure 6 shows a schematic configuration diagram of a conventional vacuum evaporation apparatus, in which 1 is a non-magnetic substrate, 2 is a cylindrical can, 3 is an inlet roller, 4 is an outlet roller, 5 is an evaporation line, and 6 is a shielding plate. be. As shown in Fig. 6, the coercive force is increased continuously on a long non-magnetic substrate 1 by a sputtering method or a vapor deposition method (including a method in which a part of evaporated atoms is ionized and vapor deposited like the ion blating method). When a small soft magnetic underlayer with high magnetic permeability is formed, due to the self-shading effect, the longitudinal direction (MO) of the substrate 1 as shown in FIG.
This results in in-plane-axis anisotropy such that the axis of hard magnetization is the axis of magnetization, and the axis of easy magnetization is the width direction (TD) as shown in FIG. 7(b). In other words, the initial magnetic permeability μ of the formed soft magnetic underlayer
I is large in the MD force direction and small in the TD direction.

Furthermore, when a disk-shaped medium is punched out from a double-layered film medium on which a vertically anisotropic film is formed, output fluctuations occur during one revolution due to the anisotropy of the soft magnetic underlayer. This situation will be explained using FIGS. 8 and 9. In the figure, 9 is a disk-shaped medium punched out from a double-layered medium consisting of a long nonmagnetic substrate 1, a soft magnetic backing layer, and a perpendicular anisotropic film. The head is A, which is a point on a concentric circle on the disk-shaped medium 10.
FIG. 9 shows how the reproduction output changes when recording and reproduction are performed after passing through point B, point B, point 0, and point D in sequence. The horizontal axis shows the passage of time, and the vertical axis shows the output, which is called an output envelope. In the figure, A, B, C, and D are disk-shaped media 10.
These correspond to point A, point B, point 0, and point D above, respectively.

The head is at point A, and at point 0 the initial magnetic permeability of the soft magnetic underlayer μi
In parallel to the low direction of , at points B and D, the initial permeability μI
Run parallel to the higher direction. As a result, as shown in FIG. 9, the output is low at points A and 0, and high at points B and D. Such output fluctuations are disadvantageous for disk-shaped media. Therefore, in order to eliminate output fluctuations, it has been necessary to make the soft magnetic underlayer isotropic.

An object of the present invention is to provide a method for easily manufacturing a two-layer perpendicular magnetic recording medium that can have an isotropic soft magnetic underlayer.

Means for Solving the Problem In order to solve this problem, the present invention provides a process for continuously forming a soft magnetic under layer on a long substrate by vapor deposition or sputtering. A magnetic field is applied near the formation portion in a direction substantially perpendicular to the film surface of the elongated substrate.

Effect As described above, by applying a magnetic field in a direction substantially perpendicular to the film surface of the elongated substrate near the soft magnetic under layer forming part, perpendicular anisotropy is induced in the soft magnetic under layer, and it is uniformly distributed in the plane. be standardized.

EXAMPLE Hereinafter, an example of the present invention will be described based on the drawings. FIG. 1 is a schematic diagram of an apparatus for depositing or sputtering a soft magnetic underlayer to explain an embodiment of the present invention.

In FIG. 1, a long non-magnetic substrate 1 is traveling along the circumferential surface of a cylindrical can 2, and along the way, it flies from an evaporation source 5 onto the surface of the substrate 1 through a gap between a shielding plate 6. A vaporized Il film of a soft magnetic stopper is formed. During sputtering, a soft magnetic target is placed at 5, and Ar(1
) and other ions. Reference numeral 7 denotes a coil placed on the shielding plate 6, and by passing a current through it, a magnetic field is applied in a direction approximately perpendicular to the film surface of the substrate 1 in the vicinity of the soft magnetic backing layer forming part. . In this case, the direction of the current does not matter. The actual magnetic flux flow 11 is shown in Figure 3 (
Shown in a).

Further, as shown in FIGS. 2(a) and 2(b), one or more pairs of magnets 68 (permanent W115, including electromagnets) having the same power facing each other may be arranged to generate a magnetic field.

This is because most of the magnetic field generated from the pair of magnets 8 with the same poles facing each other is applied in a substantially perpendicular direction to the substrate 1, and the in-plane component is small. The actual magnetic flux flow 11 is shown in Figure 3(b).
Shown below.

Furthermore, if the cylindrical can 2 is made of a ferromagnetic material at least near the circumferential surface, the magnetic field applied in a direction substantially perpendicular to the substrate 1 will be strengthened, and a greater effect can be expected.

As described above, when a magnetic field is applied in a direction substantially perpendicular to the substrate 1 near the formation part when forming a soft magnetic backing layer, perpendicular anisotropy is induced in the soft magnetic backing layer, as shown in FIG. 4(a). It becomes possible to obtain an isotropic film that is equal in the longitudinal direction (MD) and width direction (TD) as shown in b).

Next, C0-Cr is placed on the isotropic soft magnetic underlayer.
The two-layer film medium on which the I-orthotropic film is formed is punched out into a disk shape in the same manner as shown in FIG. 8 to obtain a disk-shaped medium 10. FIG. 5 shows changes in the reproduction output when the head successively passes through points A, B, 0, and D, which are concentric points on the disk-shaped medium 10, and performs recording and reproduction. The horizontal axis shows the passage of time, and the vertical axis shows the output, which is called an output envelope. In the figure, A, B, C, and D correspond to points A, 8, 0, and D on the disk-shaped medium 10, respectively. Looking at Figure 5, there is almost no output fluctuation,
The effect of making the soft magnetic underlayer isotropic is observed. Further, the effect of the present invention is great when the main components of the soft magnetic underlayer are Co, Fe, and Ni. Among these, the effects of the present invention are particularly great when the soft magnetic material contains 5 to 32% by weight of Co and 10 to 25% by weight of Go.

Next, a specific example will be described. Ga2O, Fe15. Ni65 (subscript is weight]%) was evaporated under a magnetic field as shown in Figure 1.
A soft magnetic underlayer of 00≦ was formed. A Go--Cr vertically anisotropic film was continuously formed thereon to a thickness of 2000<:. As a result, the 8-day loop of the soft magnetic backing layer as shown in Figure 4 was obtained, the coercive force was 60e, and the output envelope was as shown in Figure 5, with a good vertical A two-layer magnetic recording medium was obtained.

Effects of the Invention According to the method of the present invention, the output fluctuations of a double-layer film medium for perpendicular magnetic recording, which were conventionally large, can be suppressed to a small level.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the inside of a vacuum evaporation apparatus for explaining one embodiment of the present invention, FIG. 2 is an enlarged partial view of the main part of FIG. 1, and FIG. 3 is a diagram of the magnetic flux generated by the present invention. FIG. 4 is a graph showing the magnetic properties of the soft magnetic underlayer obtained by the present invention. FIG. 5 is a graph showing the output fluctuation of the two-layer film medium obtained by the present invention. FIG. is a schematic diagram of the internal structure of a conventional vacuum evaporation apparatus, FIG. 7 is a graph showing the magnetic characteristics of only the conventional soft magnetic underlayer, and FIG. 8 is a diagram for explaining the problems of the conventional two-layer film medium. Figure 9 shows the conventional 2L
l! It is a graph showing the output fluctuation of pA medium. 1...Nonmagnetic substrate, 2...Cylindrical key 1? N, 5...
・Evaporation source, 6... Shielding plate, 7... Coil, 8...
Magnet, 9...Double-layer film medium, 10...Disc-shaped medium Agent Yoshihiro MorimotoFigure 1Figure 2Figure 3Figure 6Figure 7 (2) B-H Ruff 0tb of Isho Wafang (HD) > Huan A'? L8*a＞'PLbtq(TO)
B-Htt-y' of Figure q

Claims (1)

[Scope of Claims] 1. In the step of continuously forming a soft magnetic backing layer on a long substrate by vapor deposition or sputtering, a film of the long substrate is formed in the vicinity of the soft magnetic backing layer formation portion. A method for manufacturing a perpendicular magnetic recording medium in which a magnetic field is applied in a direction substantially perpendicular to the surface. 2. Claim 1, characterized in that the soft magnetic underlayer is a soft magnetic material whose main components are Co, Fe, and Ni.
A method for manufacturing a perpendicular magnetic recording medium as described in . 3. The method for manufacturing a perpendicular magnetic recording medium according to claim 2, wherein the soft magnetic material contains 5 to 32% by weight of Co. 4. The method for manufacturing a perpendicular magnetic recording medium according to claim 2, wherein the soft magnetic material contains 10 to 25% by weight of Co. 5. The long substrate is run along the circumferential surface of a cylindrical can made of ferromagnetic material at least near the circumferential surface, and a soft magnetic backing layer is continuously applied along the way by vapor deposition or sputtering. A method of manufacturing a perpendicular magnetic recording medium according to any one of claims 1 to 4, characterized in that the perpendicular magnetic recording medium is formed as follows. 6. Perpendicular magnetic recording according to any one of claims 1 to 5, characterized in that the magnetic field is generated by passing a current through a coil arranged near the soft magnetic underlayer forming part. Method of manufacturing media. 7. The perpendicular magnetic field according to any one of claims 1 to 5, characterized in that the magnetic field is generated by a pair or more of magnets with the same poles facing each other and arranged in the vicinity of the soft magnetic underlayer forming part. A method for manufacturing a magnetic recording medium.