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. 25, 2008
Filed:
Mar. 06, 2007
Hiroaki Nemoto, Kanagawa, JP;
Ikuko Takekuma, Kanagawa, JP;
Yuzuru Hosoe, Tokyo, JP;
Hitachi Global Storage Technologies Netherlands B.V., AZ Amsterdam, NL;
Abstract
Embodiments in accordance with the present invention provide a perpendicular magnetic recording medium which is easy to record, offers superior thermal stability of recording magnetization, and allows high-density recording. In one embodiment, a perpendicular magnetic layer with controlled magnetic properties is used as a magnetic storage layer of a perpendicular magnetic recording medium, the magnetic properties having been controlled such that an indicator σh[%] of the dispersion of magnetization switching fields in the perpendicular magnetic layer and an indicator D[nm] of the intensity of exchange interactions, in film surface directions, in the perpendicular magnetic layer satisfy inequalities σh/27+D/90<1, and D>20. The indicators can be measured using a magnetometer.