JPS6020806B2 - magnetic recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in magnetic recording media such as magnetic cards, magnetic disks, and magnetic tapes, and particularly relates to the improvement of magnetic recording media such as magnetic cards, magnetic disks, and magnetic tapes. This is effective when forming a magnetic layer of Bi203. Specifically, Bi203
The magnetic layer is formed on a non-magnetic oxide layer coated with a non-magnetic oxide layer.

In recent years, in order to improve magnetic recording density, coating-type recording media based on acicular crystals of y-Fe203 have reached their limits, and magnetic layers are formed by plating, vapor deposition, etc. with metals, alloys, etc. The technology used as a recording medium is attracting attention.

The biggest weakness of these is that they are strongly influenced by the surface of the substrate, and even if the magnetic layer is formed using the same method and under the same conditions,
Characteristics may change, making it a practical problem. Therefore, in order to eliminate the above-mentioned conventional drawbacks, the present invention has the following features:
As shown in the drawing, the intermediate layer between a base 1 made of a polymer molded material such as vinyl chloride, polyethylene phthalate, polypropylene, or polyimide or a nonmagnetic metal material and a magnetic layer 2 made of a ferromagnetic metal or its oxide is made of Bi203. The Bi203 layer, which forms the non-magnetic oxide layer 3, can be formed on the substrate 1 by known methods such as reactive evaporation, ion plating, and sputtering, and is less affected by the manufacturing method. It's an excellent middle class.

The Bi203 layer obtained by any of these methods is smooth, which is advantageous in forming the magnetic layer 2 by known means such as vapor deposition. That is, the F obtained on the Bi203 layer
The ferromagnetic layer made of E, Co, Ni or their alloys or oxides can maintain the smoothness of the Bi203 substrate layer, making it possible to obtain a recording medium with less loss. As described above, a low-noise recording medium can be obtained.

Figure 2 shows the frequency characteristics of the noise output during direct current magnetization.Curve 4 is the case where °C o is obtained directly on a polyimide film with a thickness of 20 peaks by electron beam deposition, and curves 5 and 6 are
is the case where Bi203 layer is arranged as the intermediate layer, curve 5 is Bi203 layer at 100A/sec, curve 6 is 10A
/sec, with a film thickness of 300A, and the noise level is reduced by nearly 2MB by resistance heating, ion plating, etc., and has excellent features, compared to the above-mentioned ferromagnetic metals. By vapor deposition of , alloys, etc., stable and high performance recording media can be obtained.

In the present invention, the intermediate layer and the magnetic layer may have a multilayer structure.

. As described above, the magnetic recording medium according to the present invention has Bi20
Due to the formation of the non-magnetic oxide layer consisting of 3, the electrical properties are very improved, and its industrial potential is great.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of a magnetic recording medium according to the present invention, and FIG. 2 is a frequency characteristic diagram of the same medium and a different medium. 1...Base body, 2...Magnetic layer, 3...
...Nonmagnetic oxide layer. Figure 1 Figure 2

Claims (1)

[Claims] 1. A magnetic recording medium characterized in that a magnetic layer made of a ferromagnetic metal or its oxide is formed by interposing a nonmagnetic oxide layer made of Bi_2O_3 on the surface of a substrate made of a polymer molded product or a nonmagnetic metal material. .