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US 6,472,048 B1Granted
Magnetic recording medium and process for producing the same
AssigneeToda Kogyo Corporation
InventorYasuo Kakihara
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Abstract
A magnetic recording medium having an excellent surface smoothness comprising a substrate and a maghemite thin film formed on the substrate. The maghemite thin film has a thickness of 10 to 50 nm and a surface roughness represented by an average surface roughness (Ra) of 0.1 to 0.7 nm and a max height (Rmax) of 1 to 10 nm. The magnetic recording medium exhibits an excellent surface smoothness without deterioration in high coercive force.
Claims9
A magnetic recording medium comprising:
- a substrate;
- and
- a maghemite thin film formed on said substrate,
- said maghemite thin film having a thickness of 10 to 50 nm, and a surface roughness represented by a center line average roughness (Ra) of 0.1 to 0.7 nm and a maximum height (Rmax) of 1 to 10 nm wherein said magnetic recording medium is produced by a process comprising:
- (a) forming a magnetite thin film on a substrate;
- (b) subjecting said magnetite thin film to plasma treatment at a substrate temperature of 100 to 200° C. using an oxygen gas or an oxygen-containing mixed gas;
- and
- (c) oxidizing said magnetite thin film to transform the magnetite thin film into a Maghemite thin film.
5 more elements
A process for producing a magnetic recording medium, comprising:
- forming a magnetite thin film on a substrate;
- subjecting said magnetite thin film to plasma treatment at a substrate temperature of 100 to 200° C. using an oxygen gas or an oxygen-containing mixed gas;
- and
- oxidizing said magnetite thin film to transform the magnetite thin film into a maghemite thin film.
- wherein said maghemite thin film has a thickness of 10 to 50 nm, and a surface roughness represented by a center line average roughness (Ra) of 0.1 to 0.7 nm and a maximum height (Rmax) of 1 to 10 nm.
2 more elements
Dependencies are inferred from the claim text.