PURPOSE: To improve the durability in a humid atmosphere as well as the weather resistance by laminating three magnetic thin films each contg. a specified component as a principal component on a nonmagnetic substrate.
CONSTITUTION: The magnetic thin film 12 contg. cobalt as the principal component is formed on the nonmagnetic substrate 11 by diagonal incident vapor deposition or other method, the magnetic thin film 13 contg. iron oxide as the principal component is formed on the film 12 by diagonal incident vapor deposition or other method, and the magnetic thin film 14 contg. iron nitride as the principal component is formed on the film 13 by diagonal incident ion plating or other method to obtain an unbonded magnetic recording medium. The durability of the medium in the humid atmosphere as well as the weather resistance is improved by the resulting three-layered recording film.
YASUNAGA TADASHI
ARAI YOSHIHIRO
KITAMOTO TATSUJI
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