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:
Dec. 06, 2011
Filed:
Nov. 09, 2007
Reiko Arai, Kanagawa, JP;
Hiroyuki Suzuki, Kanagawa, JP;
Masayoshi Shimizu, Kanagawa, JP;
Hitachi Global Storage Technologies Netherlands B.V., Amsterdam, NL;
Abstract
Embodiments of the present invention provide a perpendicular magnetic recording medium which does not cause medium noise to increase due to soft magnetic underlayers, is capable of easily controlling the thickness of a nonmagnetic layer disposed between soft magnetic underlayers, and capable of improving the corrosion resistance of the soft magnetic underlayers. According to one embodiment, in a perpendicular magnetic recording medium, an adhesion layer is formed on a substrate, a soft magnetic underlayer is formed on the adhesion layer, a seed layer and an intermediate layer are formed above the soft magnetic underlayer, and a perpendicular layer is formed on the intermediate layer. The soft magnetic underlayer has a first soft magnetic layer, a second first soft magnetic layer, and an antiferromagnetic coupling layer disposed between the first soft magnetic layer and the second soft magnetic layer, the first soft magnetic layer and the second soft magnetic layer are formed of an alloy comprising Fe as a main ingredient, the antiferromagnetic coupling layer is formed of an Ru—Fe alloy, and an Fe content is from 40 at % to 75 at %.