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US 4,792,486 AGranted
Perpendicular magnetic recording medium
AssigneeVictor Company of Japan, Ltd.
InventorsYasuo Ishizaka, Noboru Watanabe, Kazuo Kimura, Eiichiro Imaoka
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Abstract
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.
Claims3
A perpendicular magnetic recording medium on which a signal is recorded and from which the signal is reproduced by a magnetic head, said perpendicular magnetic recording medium comprising:
- a recording medium base;
- a lower layer formed on the recording medium base;
- and
- an upper layer formed on the lower layer, said upper layer being made of cobalt-chromium,
- said lower layer being formed of a sputtered magnetic material which includes cobalt, chromium and at least one of niobium in a range of 2 to 10 at% and tantalum in a range of 1 to 10 at% so that said lower layer has an in-plane coercivity in a range of 10 to 220 Oe said lower layer including a layer which is substantially magnetically-isotropic.
2 more elements
Dependencies are inferred from the claim text.