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. 20, 2007
Filed:
May. 24, 2004
Hoa Van DO, Fremont, CA (US);
David Margulies, Los Gatos, CA (US);
Hal J. Rosen, Los Gatos, CA (US);
Natacha F. Supper, Campbell, CA (US);
Hoa Van Do, Fremont, CA (US);
David Margulies, Los Gatos, 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 magnetic recording medium has a laminated magnetic structure with at least three magnetic layers, wherein the magnetic layers have decreasing intrinsic coercivity Hwith distance from the write head. The write field at the center of each magnetic layer is greater than that layer's H. The magnetic layers have different compositions and/or thicknesses and thereby different values of H. The alloys used in the middle and upper magnetic layers are relatively 'high-moment' alloys that would not ordinarily be used in magnetic recording media because they have relatively low SNR, but the overall SNR of the laminated magnetic structure is improved because of the effect of lamination. The middle and upper magnetic layers can be made substantially thinner, which enables the magnetic layers to be located closer to the write head, thereby exposing each of the magnetic layers to a higher write field.