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:
Nov. 10, 2015
Filed:
Oct. 10, 2013
Wd Media (Singapore) Pte. Ltd., Irvine, CA (US);
Takahiro Onoue, Singapore, JP;
WD Media (Singapore) Pte. Ltd., Singapore, SG;
Abstract
A perpendicular magnetic recording mediumhaving a magnetic recording layer, wherein a particle diameter of crystal grains in layerimproves a SNR while a high coercive force is maintained. There also is at least a ground layer, a first magnetic recording layer, and a second magnetic recording layerin this order on a disk base. The first layerand the second layerare ferromagnetic layers, each having a granular structure in which a grain boundary part made of a non-magnetic substance is formed between crystal grains each grown in a columnar shape, and A<B when an average particle diameter of the crystal grains in the first magnetic recording layeris taken as A nm and an average particle diameter of the crystal grains in the second magnetic recording layeris taken as B nm.