Magneto-optical recording medium
AssigneeSharp Kabushiki Kaisha
InventorNobuyuki Takamori
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Abstract
An amorphous magnetic thin film of TbDyFeCo alloy is described, which is a multi-layer film formed by alternately laminating a TbFeCo layer and a DyFeCo layer on a substrate and has an axis of easy magnetization perpendicular to a film surface, wherein, when the composition of the magnetic thin film is represented by Tb.sub.x Dy.sub.y (Fe.sub.1 -.sub.z Co.sub.z)1-(x+y) and when x, y and z are within ranges of 0<x.ltoreq.0.12, 0<y.ltoreq.0.12, and 0<z .ltoreq.0.30, a condition to be satisfied by x and y is 0.25.ltoreq.x/(x+y). Consequently, an inexpensive magneto-optical recording medium with an improved C/N ratio is manufactured.
Claims4
A magneto-optical recording medium comprising:
- a substrate;
- and
- a recording layer having a quaternary amorphous alloy thin film including terbium, dysprosium, iron and cobalt on said substrate, said quaternary amorphous alloy thin film (a) being made of a multi-layer film formed by laminating alternating layers of a TbFeCo layer and a DyFeCo layer and (b) having an axis of easy magnetization perpendicular to the surface of the recording layer,
- wherein, when a composition of said quaternary amorphous alloy film is represented by Tb.sub.x Dy.sub.y (Fe.sub.1-z Co.sub.z).sub.1-(x+y), x, y and z are within the ranges 0<x.ltoreq.0.12, 0<y.ltoreq.0.12, and 0<z.ltoreq.0.30, and x and y satisfy 0.25.ltoreq.x/(x+y), and
- wherein said multi-layer film comprises at least about 20 total layers of alternating TbFeCo and DyFeCo.
Dependencies are inferred from the claim text.