The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 02, 1999
Filed:
Aug. 15, 1997
Takeo Kawase, Suwa, JP;
Masaya Ishida, Suwa, JP;
Satoshi Nebashi, Suwa, JP;
Satoshi Shimokawato, Suwa, JP;
Toshiaki Mikoshiba, Suwa, JP;
Shoji Hoshina, Suwa, JP;
Hiromu Miyazawa, Suwa, JP;
Atsushi Takakuwa, Suwa, JP;
Seiko Epson Corporation, Tokyo, JP;
Abstract
In a magneto-optical recording medium, a first dielectric layer 12, a recording layer 13, an auxiliary recording layer 14, a second dielectric layer 15 and a reflective layer 16 are sequentially laminated on a transparent substrate 11. Recording layer 14 is formed of a rare-earth transition-metal amorphous alloy having a film thickness of about several hundreds angstroms. Auxiliary recording layer 14 is also formed of a rare-earth transition-metal amorphous alloy. However, the Curie temperature T.sub.C2 of auxiliary recording layer 14 is 10.degree. K or more higher than the Curie temperature T.sub.C1 of recording layer 13, and the film thickness of auxiliary recording layer is ultra-thin, such as, 70 .ANG. or less. Further, the squareness ratio of auxiliary recording layer 14 at the Curie temperature T.sub.C1 of recording layer 13 is 0.7 or higher. These characteristics of auxiliary recording layer 14 may be realized by selecting the composition of auxiliary recording layer 14 or by lowering the density of the layer. In addition, a transition metal, such as, Fe or Co, or a non-magnetic metal, such as, Pt, Al, Ti or Cr, or a nitride of rare-earth transition-metal amorphous alloy may be employed as the material for auxiliary recording layer 14.