| 摘要 |
PURPOSE:To obtain a long-life recording medium which permits thermomagnetical writing of information with a laser beam and reading out of said information by irradiation of another polarized laser light by forming a thin amorphous magnetic alloy layer on a transparent non-magnetic base and forming a protective film consisting of a non-oxidative material on the surface of said layer. CONSTITUTION:A low coercive force layer 2 consisting of an amorphous Gd0.20 Fe0.08 alloy, etc. having the high Curie point to permit vertical magnetization is formed on a transparent non-magnetic base 1 consisting of glass, polymethyl methacrylate, etc. then a high coercive force layer 3 consisting of an amorphous alloy such as Th0.23Fe0.77, etc. is formed thereon. The layer 2 is formed into the thin layer of about 400-600Angstrom and the layer 3 about 200-400Angstrom . A protective layer 4 consisting of a non-oxidative material such as metallic nitride or carbide of TiN, TaC, etc. is further formed on the layer 3 to manufacture a vertical thermomagnetic recording medium 10. The recording medium which permits thermomagnetical writing with a laser beam under impression of a bias magnetic field and reading out by utilizing a Kerr effect with another polarized laser light, maintains the initial coercive force with substantially no deterioration with age and has stable magnetic recording property is thus obtd.
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