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:
Dec. 05, 1995
Filed:
Nov. 23, 1994
Masaki Itoh, Tokyo, JP;
Eizoh Fukami, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
A magnetooptical recording medium having a higher recording density, improved bit error rate and superior weather resistance and a recording and playback method for the same are provided. The magnetooptical recording medium has a first magnetooptical layer having a high Curie temperature a second perpendicularly magnetizable magnetooptical layer having a low Curie temperature and a third perpendicularly magnetizable magnetooptical layer having an intermediate Curie temperature set between the Curie temperatures of the first and second magnetooptical layers, laminated in this order on a substrate. The first, second and third magnetooptical layers are formed respectively of amorphous alloys containing GdFeCo, TbFeTi and TbFeCoTi as the main component thereof. The first, second and third magnetooptical layers are exchange-coupled at 10.degree. C. to 90.degree. C., and the first and third magnetooptical layers are not magnetostatically coupled in the external magnetic field for reading use at the temperature at which the magnetization of the second magnetooptical layer is diminished.