Hoya Corporation

Kivoshi Sato

Hisao Kawai

Keiji Moroishi

Isao Kawasumi

According to the present invention, a magnetic recording medium comprises a glass substrate, a first under layer, a second under layer, a magnetic layer, a protective layer and a lubricant layer in the named order. The first under layer is formed on a glass plate, a surface of which is highly polished. The second under layer is formed, on the first under layer, of a material differing from a material of the first under layer, and has a thickness greater than a thickness of the first under layer. The magnetic layer is formed on the second under layer. The protective layer is formed on the magnetic layer, on whose surface a texture due to dispersed hard minute particles appears. The lubricant layer is formed on the protective layer. For such a magnetic recording medium, a property of the material used for the first under layer is that it promotes the crystalline growth of the second under layer, which is formed on the first under layer to support the crystalline growth of the magnetic layer that is deposited on the second under layer; and another property is that it relieves internal stress resulting from a difference in thermal expansion between the second under layer and the glass substrate.

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Nirasaki, Japan

Kivoshi Sato