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. 23, 2015
Filed:
Sep. 16, 2009
Takahiro Onoue, Singapore, SG;
Teiichiro Umezawa, Singapore, SG;
Takahiro Onoue, Singapore, SG;
Teiichiro Umezawa, Singapore, SG;
WD Media (Singapore) Pte. Ltd., Singapore, SG;
Abstract
An object of the present invention is to provide a perpendicular magnetic recording medium the SNR of which is further improved while a high coercive force Hc is secured so that a higher recoding density can be achieved. The structure of a perpendicular magnetic recording mediumaccording to the present invention includes, on a base, at least a first magnetic recording layerhaving a granular structure in which a non-magnetic grain boundary portion is formed between crystal particles grown in a columnar shape; a non-magnetic split layercontaining Ru disposed on the first magnetic layer; and a second magnetic recording layerthat is disposed on the split layer and that has a granular structure in which a non-magnetic grain boundary portion is formed between crystal particles grown in a columnar shape, wherein the first magnetic layer and the second magnetic layer contain oxides that form the grain boundary, and when an oxide content of the first magnetic layer is represented by A and an oxide content of the second magnetic layer is represented by B, a relationship between the oxide contents A/B is in the range of 0.5<A/B<1.0.