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:
Oct. 30, 2012
Filed:
May. 30, 2008
Yoshiaki Sonobe, Shinjuku-ku, JP;
Kong Kim, Tokyo, JP;
Yoshiaki Sonobe, Shinjuku-ku, JP;
Kong Kim, Tokyo, JP;
WD Media (Singapore) Pte. Ltd., Singapore, SG;
Abstract
[PROBLEMS] To provide a process for producing a magnetic recording medium, which can simultaneously realize increased high recording density, high impact resistance, and prevention of corrosion, by providing an underlayer which, even when formed at a low gas pressure, can exhibit a high level of coercive force. [MEANS FOR SOLVING PROBLEMS] A process for producing a perpendicular magnetic recording medium, comprising the step of forming a nonmagnetic underlayer () having a granular structure, in which crystal particles are grown in a column form, on a substrate, and forming a magnetic recording layer () having a granular structure in which magnetic particles are grown in a column form. The process is characterized in that the underlayer () is any one of CoCr or CoCrX (wherein X is a nonmagnetic material), CoCr-oxide, and CoCrX-oxide, and the film forming gas pressure of the underlayer () is not more than 4 Pa.