Victor Company of Japan, Limited

Eiichiro Imaoka

Noboru Watanabe

Yasuo Ishizaka

Kazuo Kimura

A perpendicular magnetic recording medium comprises a recording medium base, a lower layer formed on the recording medium base, and an upper layer formed on the lower layer. The lower layer is made of a first material including cobalt, chromium and one or more elements other than cobalt and chromium. On the other hand, the upper layer is made of a second material including cobalt, chromium and one or more elements other than cobalt and chromium. A quantity of the one or more elements added to cobalt and chromium making up the second material is less than a quantity of the one or more elements added to cobalt and chromium making up the first material.

Perpendicular magnetic recording medium

A perpendicular magnetic recording medium comprises a recording medium base, a lower layer formed on the recording medium base, and an upper layer formed on the lower layer. The upper layer is made of cobalt-chromium, and the lower layer at least includes cobalt and chromium.

A perpendicular magnetic recording and reproducing system records and reproduces a signal on and from a perpendicular magnetic recording medium comprising a magnetic layer which is made from one magnetic material and is constituted by a layer having a low coercivity and a layer having a high coercivity on top of the layer having the low coercivity, by use of a ring core head and utilizes the layer having the low coercivity as a high permeability layer and the layer having the high coercivity as a perpendicular magnetization layer.

Perpendicular magnetic recording and reproducing system

A perpendicular magnetic recording medium comprises a recording medium base, a low coercivity layer formed on the recording medium base and having a low coercivity in an in-plane direction thereof, and a high coercivity layer formed on the low coercivity layer and having a high coercivity in a direction perpendicular to a surface of the low coercivity layer. The low coercivity layer and the high coercivity layer are formed from the same magnetic material and constitute a magnetic layer. A method of manufacturing this perpendicular magnetic recording medium comprises a single magnetic layer forming process of successively and continuously forming the low coercivity layer and the high coercivity layer on the recording medium base by using the same magnetic material as a depositing material.

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Sagamihara, Japan

Eiichiro Imaoka