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:
Feb. 14, 1995
Filed:
Sep. 21, 1992
Jun Saito, Tokyo, JP;
Tetsuo Hosokawa, Yokohama, JP;
Akio Okamuro, Yokohama, JP;
Hiroyuki Matsumoto, Tokyo, JP;
Haruhisa Iida, Yokohama, JP;
Satomi Kokai, Yokohama, JP;
Hideki Akasaka, Kamagaya, JP;
Nikon Corporation, Tokyo, JP;
Abstract
A medium includes a readout layer, a memory layer, an adjusting layer for an exchange coupling force .sigma..sub.W, and a writing layer, and can perform an over-write operation upon radiation of a modulated laser beam. The readout layer essentially consists of GdFeCo, the memory layer essentially consists of TbFeCo, the adjusting layer essentially consists of GdFeCo, and the writing layer essentially consists of DyFeCo. The C/N ratio of the medium exceeds 53 dB. The C/N ratio is a value obtained when a plurality of mark.sup.H having a period of 1.6 .mu.m are written, and are read out so that medium noise is maximized as compared to other noise components.