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:
Jan. 03, 1995
Filed:
Oct. 05, 1993
Sony Corporation, Tokyo, JP;
Abstract
The present invention adopts as the basic structure of its thermomagnetic recording medium an arrangement consisting of a first and a second magnetic thin film having perpendicular anisotropy and a third magnetic thin film having in-plane magnetic anisotropy or small perpendicular magnetic anisotropy interposed therebetween, formed into a laminated structure by being magnetically coupled to the adjoining films in turn, modulates and switches, in accordance with information to be recorded, a first heating condition and a second heating condition, with the medium applied with a predetermined external magnetic field H.sub.ex in the direction perpendicular to the plane of the film, the first condition being that for raising temperature of the medium to a first temperature T.sub.1 which is virtually above the Curie temperature T.sub.C1 of the first magnetic thin film and not causing reversal of the magnetic moment in the second magnetic thin film and the second condition being that for raising temperature of the same to a second temperature T.sub.2 which is virtually above the Curie temperature T.sub.C1 and sufficient to cause reversal of the magnetic moment in the second magnetic thin film, to thereby form an information bit (magnetic domains) in the first magnetic thin film, and adapts during the course the medium is cooled from the heated states such that two states established by the different relationships between the directions of magnetization of the first and second magnetic thin films are finally formed whereby the recording of the information is performed to achieve overwriting.