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:
Jun. 13, 2006
Filed:
Jan. 27, 2004
Tetsuhiro Sakamoto, Tokyo, JP;
Kazutomo Miyata, Miyagi, JP;
Teruyuki Ota, Miyagi, JP;
Makoto Watanabe, Miyagi, JP;
Yasuhito Tanaka, Tokyo, JP;
Goro Fujita, Kanagawa, JP;
Takeshi Miki, Tokyo, JP;
Kazuhiko Fujiie, Kanagawa, JP;
Tetsuhiro Sakamoto, Tokyo, JP;
Kazutomo Miyata, Miyagi, JP;
Teruyuki Ota, Miyagi, JP;
Makoto Watanabe, Miyagi, JP;
Yasuhito Tanaka, Tokyo, JP;
Goro Fujita, Kanagawa, JP;
Takeshi Miki, Tokyo, JP;
Kazuhiko Fujiie, Kanagawa, JP;
Sony Corporation, Tokyo, JP;
Abstract
A magneto-optical recording medium includes a first magnetic layer (reproduction layer), a second magnetic layer (control layer), a third magnetic layer (blocking layer), and a fourth magnetic layer (recording layer) having respective Curie temperatures T, T, Tand T. The Curie temperatures of the layers satisfy the relationships T>T>Tand T>T. In addition, the magnetic anisotropy of the third magnetic layer Kis greater than that of the second magnetic layer K. A magnetic domain wall in the first magnetic layer in front of the spot irradiated by the reproduction light in the direction of travel is displaced toward the peak temperature portion so that a recorded domain is expanded. Displacement in the spot direction of a domain wall in the first magnetic layer behind the reproduction light spot in the direction of travel is suppressed. The second and third magnetic layers control the magnetic exchange coupling between the first and fourth magnetic layers.