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:
Feb. 22, 2005
Filed:
Dec. 26, 2001
Kiwamu Tanahashi, Kokubunji, JP;
Atsushi Kikugawa, Higashimurayama, JP;
Yukio Honda, Fuchu, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
Disclosed are a double-layer perpendicular magnetic recording medium having a high medium S/N at a recording density of 50 Gbit or more per square inch and a magnetic storage apparatus with high reliability, which shows a low error rate. In the perpendicular magnetic recording medium in which a pre-coating layer, a soft magnetic underlayer, an intermediate layer, and a perpendicular recording layer are sequentially formed on a substrate, the soft magnetic underlayer contains Fe, Ta and C as main components, a Ta concentration is set to a range from 8 at % to 15 at % , and a ratio of a C concentration to the Ta concentration (C concentration/Ta concentration) is set to a range from 0.5 to 0.9.