Magnetic recording medium and magnetic recording method for digital image signal
AssigneeSony Corporation
InventorsHiroshi Uchiyama, Naoki Honda, Takanori Sato
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Abstract
The coefficient k.sub.1 of linear expansion in a temperature range from 50.degree. to 300.degree. C. of a non-magnetic support member of a recording medium, before a Co-Cr alloy film is formed thereon, is less than 0 mm/mm .degree.C., and the coefficient k.sub.2 of linear expansion in a temperature range from 50.degree. to 300.degree. C. of that support member after the Co-Cr alloy film is formed is less than 0.3.times.10.sup.-5 mm/mm .degree.C. The alloy film also includes carbon in the magnetic layer, and a protective film comprised of carbon is further formed on the magnetic layer. The recording medium is particularly adapted for perpendicular magnetic recording.
Claims3
A magnetic recording medium formed of a metal magnetic thin film on a non-magnetic support member, said metal magnetic thin film consisting essentially of cobalt (Co) and chromium (Cr) as its major components and said non-magnetic support member consisting essentially of a polyimide film having a coefficient of linear expansion k.sub.1 less than 0 mm/mm.degree.C. in a temperature range from 200.degree. C. to 300.degree. C. before the metal magnetic thin film is formed thereon, and a coefficient of linear expansion k.sub.2 less than 0.3.times.10.sup.-5 mm/mm.degree.C. in a temperature range from 200.degree. C. to 300.degree. C. after the metal magnetic thin film is formed thereon.
Dependencies are inferred from the claim text.