JPH01320618A - Magnetic recording medium and its production - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording medium for perpendicular magnetic recording suitable for high-density recording and a method for manufacturing the same.

Conventional technology Perpendicular magnetic recording is attracting attention as a magnetic recording technology that can exceed the limits of high density achieved by in-plane magnetization recording (IEICE Magnetic Recording Study Group Materials-mRss-16). .

To realize such high-density recording, a ferromagnetic metal thin film disposed on a substrate requires a magnetized film that can arrange residual magnetization in an antiparallel direction perpendicular to the film surface, a so-called perpendicular magnetized film. 15-23wt of Or at about 0.2-0.5μm
% co -Gjr sputtered film is the best in terms of performance, and proposals have been made to speed it up for practical use (4th Japan Society of Applied Magnetics 60 people-4. Special Publication 62-6
6575).

Problems to be Solved by the Invention However, G
The o-Or perpendicularly magnetized film has other problems besides its low film formation speed. In particular, durability under high-speed sliding conditions in contact with a magnetic head is an important issue.
Regardless of the form of tape, abrasion powder is generated, and tape is used in electromagnetic conversion systems.

There is a problem in that either one or both of the disk and the head is damaged, making it impossible to maintain excellent high-density recording characteristics, and improvements have been desired.

The present invention was made in view of the above-mentioned circumstances, and is intended to improve the durability of a perpendicularly magnetized film produced by a sputtering method with excellent performance.

Means for Solving the Problems In order to solve the above problems, the magnetic recording medium of the present invention comprises:
0.04 abnormal protrusions on a polymer film with depressions
The magnetic recording layer is a perpendicularly magnetized film with a diameter of less than K/(μm)2, and the manufacturing method for such a magnetic recording medium is to apply 3QO (VSeC) while winding a polymer film having dimples.
) A perpendicularly magnetized film is formed using the above-described high-speed sputtering method.

Function The magnetic recording medium of the present invention is characterized by the fact that the protrusions produced by the abnormal growth of crystals formed by the sputtering method, which aims to increase the speed, are stochastically formed in the hollows of the polymer film, so that they virtually no longer act as protrusions, and thus have excellent durability. sex will be improved.

EXAMPLE Hereinafter, an example of the magnetic recording medium of the present invention and its manufacturing method will be described with reference to the drawings.

FIG. 1 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 Figure 1, 1 is a polymer film such as a polyester film, 2 is a shape transfer roller for forming indentations in the polymer film such as a polyester film, 3 is a cooling can, 4 is an unwinding shaft, and 6 is a winding shaft. 6 is a pressure roller, 7 and 8 are magnetron cathodes, 9 is a gas introduction boat, 1o is a variable valve, 11 is a free roller,
12 is a vacuum container, and 13 is a vacuum evacuation system.

FIG. 2 is an enlarged sectional view showing an embodiment of the magnetic recording medium of the present invention, in which 14 is a polymer film such as polyethylene terephthalate, polyetheretherketone, polyphenylene sulfide, etc., and 15 is a recess. For the depression 16, it is sufficient if the depth is 0.05 μm to 0.1 μm.
The diameter is preferably about 0.06 μm to 0.4 μm at the surface, and the density is preferably 0.01 to 5 cells/(μm) 2 . 16 is a ferromagnetic metal thin film capable of perpendicular magnetization, Go-Or, Go-Ti
, Go-W, Go-Mo, Go-Cr-Nb, etc., with perpendicular magnetization, preferably having abnormal protrusions of 0.04 pieces/(μm) or less. This film was formed using a high-speed sputtering method of 30o (input/5ec) or more, and the film thickness was 0.05
The thickness is preferably from .mu.m to 0.3 .mu.m, and the structure is such that the abnormal growth is concentrated in the depression so that it no longer functions as a substantial abnormal protrusion. 17 is a protective layer, which combines a protective film such as a plasma polymerized film, an oxide film, a nitride film, an amorphous carbon film, etc. with a lubricant such as a fatty acid, a fatty acid amide, or a fluorine oil, and has a thickness of 200 mm in consideration of spacing loss. It is preferable that the number is 8 or less. The present invention is applicable not only to magnetic tapes but also to magnetic disks.

Examples of the present invention will now be described in more detail in comparison with comparative examples.

In the apparatus shown in Figure 1, the diameters of the shape transfer roller and cooling can are both socm, and the surface of the shape transfer roller has a diameter of 0.
．． A material coated with 2 pieces/(μm)2 of 1 μm ZrO2 fine particles was used.

In the example, a polyethylene terephthalate film with a thickness of 10 μm (average surface roughness: 26 mm) was used, the temperature of the shape transfer roller 2 was raised to 70°C, and the surface was nipped with butyl rubber with a pressure of 2 kghf along the surface. After forming a dent in the area, use Go-Or (Conia 9, eWt) with two targets for 13.56 (M 7).

4.2 (KW), Ar, 4X10 (Torr')o
Conditional Tesva sotering was performed. The sputtering speed was 410 (in/SθC). Same tube can is +20
℃, the adhesion of the A side of the film to the can surface was improved by electrostatic attraction to prevent heat loss. In addition, the input of high-frequency power was increased to increase the speed.

Under these conditions, a Go-Or perpendicular magnetization film with a thickness of 0.15 μm was formed, and on top of that, 10 layers were formed by plasma polymerization using hexamethylcyclotrisilazane as a monomer gas, and on top of that, perfluorostearic acid was formed by vacuum evaporation for 50 layers. Acid, 8
It was made into millimeter-wide magnetic tape.

On the other hand, in a comparative example, a magnetic tape with a width of 8ε was obtained under the same conditions as in the example except that it was passed only along the cooling can without passing through the shape transfer roller.

With 8mm video modified from both, gap length o, 1
8μm amorphous head allows bit length of 0.25
A digital signal with a track pitch of 5 μm was recorded, and the reproduction output was compared. There was no difference in the initial values between the Examples and Comparative Examples, but as a result of repeated regeneration at 40° C. and 15% RH, the Examples showed -0, 5 to -0. All 10 windings tested were within the range of 8 (dB), but in the comparative example, the initial value was
The average value of 10 turns is -3,9 (dB) after 25 times, and -2,
The range of variation was large, ranging from 1 to -g,a (dB). As a result of investigating the surface of the tape, the number of abnormal protrusions in the example was 0.02 pieces/(μm), and the number of abnormal protrusions in the comparative example was 0.9 pieces/(μm).
An abnormal protrusion (μm) was observed.

Figure 3 summarizes the experimental results including other examples.
This shows that if high-density recording is performed with a track pitch of 7 μm or less, durability can be ensured if abnormal protrusions are controlled to 0.04 pieces/(μm 2 ) or less. FIG. 3 shows Go-Mo in addition to Co-Or.

Go-Cr-Nb, (density of hollow, o, 01~
6 pieces/(μm) 2 diameter 0.06-0.4μm depth, 0.0
This is a summary of the results mainly for those manufactured under conditions of 5 to 0.1 μm. Effect of the Invention As is clear from the above explanation, this is due to the abnormal growth of crystals formed by sputtering method aimed at increasing speed. Since the protrusions are stochastically formed in the depressions of the polymer film, they essentially no longer act as protrusions, improving durability.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of essential parts of a magnetic recording medium manufacturing apparatus used to carry out the manufacturing method of the present invention, and FIG. 2 is an enlarged cross-sectional view showing an embodiment of the magnetic recording medium of the present invention. FIG. 3 is a characteristic diagram showing the relationship between abnormal protrusion density and output regarding the present invention. 1.14...Polymer film, 2...
Cylindrical camp, 3...Cylindrical camp B, 6...
...Target Notom, 7...Target B-1
, s...Target B-2, 15...
Recessed portion, 16... Perpendicular magnetization film. Name of agent: Patent attorney Toshio Nakao and 1 other person/-
--Shimago σ film δ-dage-y)β-2 Figure 1 14--Issho Akako Fuishimuno! ;--<+2g Fig. 3 θD/ 0.7 1.0

Claims (2)

[Claims] (1) A magnetic recording medium characterized in that a perpendicular magnetization film having abnormal protrusions of 0.04/(μm)^2 or less is disposed on a polymer film having depressions. (2) While winding up the polymer film with depressions,
A method for manufacturing a magnetic recording medium, characterized in that a perpendicular magnetization film is formed by a high-speed sputtering method of 300 (Å/sec) or more.