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. 10, 2009
Filed:
Apr. 12, 2006
Eric E. Fullerton, Morgan Hill, CA (US);
David Margulies, Salinas, CA (US);
Hal J. Rosen, Los Gatos, CA (US);
Natacha F. Supper, Campbell, CA (US);
Eric E. Fullerton, Morgan Hill, CA (US);
David Margulies, Salinas, CA (US);
Hal J. Rosen, Los Gatos, CA (US);
Natacha F. Supper, Campbell, CA (US);
Hitachi Global Storage Technologies Netherlands B.V., Amsterdam, NL;
Abstract
A laminated perpendicular magnetic recording medium has two recording layers (RLand RL) that are separated and magnetically decoupled by a nonmagnetic spacer layer (SL). The SL has a thickness and composition to assure there is no antiferromagnetic or ferromagnetic coupling between RLand RL. Thus in the presence of the write field, RLand RLrespond independently and become oriented with the direction of the write field. Each RL is an 'exchange-spring' type magnetic recording layer formed of two ferromagnetic layers (MAGand MAG) that have substantially perpendicular magnetic anisotropy and are ferromagnetically exchange-coupled by a nonmagnetic or weakly ferromagnetic coupling layer (CL). The medium takes advantage of lamination to attain higher signal-to-noise ratio (SNR) yet has improved writability as a result of each RL being an exchange-spring type RL.