JPS60202525A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain the titled recording medium having excellent magnetic characteristics and to improve the preparation conditions by forming an In layer and a metallic magnetic layer successively on a nonmagnetic substrate with vapor plating. CONSTITUTION:In a vapor deposition apparatus 1, In is firstly vapor-deposited on a traveling nonmagnetic substrate 4 from an In vapor deposition source 7 to form an In vapor-deposited film on the substrate 4. Succeedingly, a metallic magnetic material is vapor-deposited thereon from a metallic magnetic material vapor deposition source 8 to deposite and form a metallic magnetic layer. High coercive force and high squareness ratio can be obtained in this way. Since the undercoat In layer consists of a low-melting point metal, the film can be formed at low temps. of the substrate. Accordingly, a high molecular film having inferior heat resistance can be used as the nonmagnetic substrate.

Description

[Detailed description of the invention] Industrial applications The present invention relates to magnetic recording media.

BACKGROUND TECHNOLOGY AND PROBLEMS In recent years, for the purpose of increasing the density of magnetic recording, ferromagnetic materials such as Co, Pa, Nl, or alloys thereof have been produced on magnetic thin-film magnetic recording media, that is, non-magnetic substrates, by methods such as vacuum evaporation and sputtering. Research into magnetic recording media in which thin films are formed is active.

In order to obtain a high coercive force Hc in the in-plane direction in such a magnetic *ii+ type magnetic recording medium, a ferromagnetic metal material is obliquely deposited on a non-magnetic substrate (by the so-called oblique deposition method) to form a magnetic layer. A method of forming a magnetic layer on a non-magnetic substrate, or a method of forming a magnetic layer by vapor depositing Co on a non-magnetic substrate using Co as a base at a substrate temperature of 300° C. or higher has been proposed.

However, in the case of the former oblique evaporation method, the evaporation efficiency was as low as a few percent, causing problems in productivity. Moreover, in the latter method, since it is necessary to raise the temperature of the substrate, there is a drawback that it is impossible to use a Todoroki molecular film, which has poor heat resistance, such as polyethylene terephthalate, as a nonmagnetic substrate.

Purpose of the Invention In view of the above points, the present invention has excellent magnetic properties and
The present invention provides a magnetic recording medium with improved manufacturing conditions.

Summary of the Invention The present invention is a magnetic recording medium in which an In layer and a metal magnetic layer are successively formed on a nonmagnetic substrate by vapor phase plating such as vapor deposition or sputtering.

In the magnetic recording medium of the present invention, high coercive force and squareness ratio can be obtained, and the magnetic layer can be formed at a low substrate temperature, thereby improving the manufacturing conditions of the magnetic recording medium.

Example The present invention will be explained in detail below.

In the present invention, a magnetic recording medium is obtained by continuously forming an In layer and a metal magnetic layer on a nonmagnetic substrate by so-called vapor phase plating such as vapor deposition or sputtering.

As the nonmagnetic substrate, for example, a polymer film such as polyethylene terephthalate, polyamide, polyamideimide, polyimide, etc. can be used.

The underlying In layer is deposited on the nonmagnetic substrate by vapor phase plating such as evaporation or sputtering, and its thickness is selected from 50 to 500 layers.

The metal magnetic layer is made of Co, Pg, or Ni by vapor phase plating such as evaporation or sputtering on the In layer.
Alternatively, the alloy can be formed by depositing the alloy to a thickness of 100 to 1000 layers.

Further, the temperature of the nonmagnetic substrate during vapor phase plating of the In layer and the metal magnetic layer can be selected from room temperature to about 100°C.

FIG. 1 shows a vapor deposition apparatus used in the present invention.

This vapor deposition apparatus ill is provided with a metal can (3) in a vacuum chamber (2), and a non-magnetic substrate (4), for example, runs between a supply reel (5) and a take-up reel (6) surrounding this. It is done like this. On the other hand, an In evaporation source (7) and an evaporation source for the metal magnetic layer, for example, a Co
evaporation sources (8) are arranged. (9) is a shielding plate that mutually shields the metal vapor flows from the deposition sources (7) and (8), and extends from between the deposition sources (7) and (8) to the front of the metal can (3). provided. 01 is a shutter placed between each vapor deposition source (7) and (8) and the metal can (3). Incidentally, the vapor deposition sources (7) and (8) are configured such that the vapor deposition material is vaporized by the impact of electrons or an electron beam from a gun (not shown), for example. In this device, while the non-magnetic substrate (4) is traveling, In is first vapor deposited from the In vapor deposition source (7) to form an In vapor deposition film on the substrate (4), and then, for example, Co vapor is deposited on this. Co from source (8) is deposited to form a metallic magnetic layer.

Example 1 Using the above-mentioned vapor deposition apparatus (11), In was vapor-deposited on a non-magnetic substrate (4) made of a polyimide film, and then Go was vapor-deposited thereon to a thickness of 300 nm to form a co-coat layer on the In base layer.
A magnetic layer was applied. At this time, In was deposited with various thicknesses to produce each magnetic recording medium.

The magnetic recording media obtained by vapor deposition at a substrate temperature of room temperature are referred to as Shiryo ^-1, ^-2, A-3, and 8-4, and each magnetic recording medium obtained by vapor deposition at a substrate temperature of 110 ° C. Sample B-
1, B-2, B-3 and B-4. Table 1 shows the preparation conditions for each sample.

Table 1 The results of measuring the coercive force Hc for each of the above samples are shown in Figure 2, and the results of measuring the rectangular non-R3 are shown in Figure 3. In the same figure, curves (1) and (1) indicate -1 ~A-4, curve (II), (It/) is for samples B-1~B-
4.

As is clear from Figures 2 and 3, the In underlayer is effective in improving coercive force, and the squareness ratio Rs is as high as 80% or more. In this example, the In layer and Co layer are formed by almost vertical deposition, so the coercive force Hc and the squareness ratio Rs are anisotropic within the film plane. There was no gender, and it was Tomo fishing.

The film can be formed at a substrate temperature below the glass transition temperature of polyethylene terephthalate, that is, about 80°C.

Therefore, it is possible to use polyethylene terephthalate film, which has poor heat resistance, as the nonmagnetic substrate.

Note that the metal magnetic layer is not limited to one layer, and may have a multilayer structure with the above-mentioned In underlayer interposed therebetween.

Moreover, although the In layer and the metal magnetic layer were formed by vapor deposition on the upper side, they can also be formed by sputtering or the like.

Effects of the Invention According to the present invention described above, by forming a metal magnetic layer on a nonmagnetic substrate via an In layer, a high coercive force He and a high squareness ratio Rs can be obtained. and,
Since the underlying In layer is a low melting point metal and the film can be formed at a low substrate temperature of, for example, about 80° C. or less, it is possible to use a polymer film, particularly a polyethylene terephthalate film, which has poor heat resistance as a nonmagnetic substrate.

Furthermore, since the metal magnetic layer is formed by vertical vapor phase plating, the banking of the metal magnetic layer becomes dense and the magnetic flux density increases. Furthermore, compared to the oblique evaporation method, since the method is vertical evaporation, the evaporation efficiency is higher and productivity is improved. Furthermore, since it is a magnetic layer that is magnetically isotropic in the plane, it has an extremely wide range of applications such as tapes and disks.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an example of a vapor deposition apparatus applied to the present invention, FIG. 2 is a characteristic diagram showing the relationship between the coercive force and the thickness of an In layer in an example of the present invention, and FIG. FIG. 3 is a characteristic diagram showing the relationship between the squareness ratio and the layer thickness. (2) is a vacuum chamber, (3) is a metal can, (4)
15116) is a non-magnetic substrate, 15116) is a reel, (7) is an In vapor deposition source, and (8) is a metal magnetic material vapor deposition source. Figure 2 Figure 3 1n4aJl? (λ)

Claims (1)

[Claims] A magnetic recording medium comprising 11 layers and a metal magnetic layer successively formed on a non-magnetic substrate by vapor phase plating.