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:
Apr. 12, 2011
Filed:
Sep. 26, 2008
Takayuki Ichihara, Tokyo, JP;
Masayoshi Shimizu, Kanagawa, JP;
Takayuki Ichihara, Tokyo, JP;
Masayoshi Shimizu, Kanagawa, JP;
Hitachi Global Storage Technologies Netherlands BV, Amsterdam, NL;
Abstract
Embodiments of the present invention help to provide a discrete track medium for realizing a high track density in a low price by adopting a configuration, in which filling of a non-magnetic material into a guard band portion and smoothing processing of a medium surface are not required. According to one embodiment, a perpendicular magnetic recording medium, on the non-magnetic substrate, includes at least: a soft magnetic underlayer; a first recording layer including a crystal grain having a magnetic property and a non-magnetic grain boundary having an oxide, as a main component, surrounding the crystal grain; a second recording layer containing a ferromagnetic metal as a main component and not containing an oxide; and at least one non-magnetic layer provided between the first recording layer and the second recording layer. A recording track portion for magnetically recording information and a guard band portion provided between adjacent recording track portions are included in the perpendicular magnetic recording medium. The relationship between the total thickness tof the non-magnetic layer in the guard band portion and the total thickness tof the non-magnetic layer in the recording track portion is set as t>t