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:
May. 15, 2007
Filed:
Nov. 04, 2003
Reiko Arai, Odawara, JP;
Kiwamu Tanahashi, Kokubunji, JP;
Atsushi Kikugawa, Higashimurayama, JP;
Hitachi Global Storage Technologies Japan, Ltd., Odawara-shi, JP;
Abstract
A magnetic recording/reproducing apparatus is disclosed with high storage capability. The apparatus also prevents fluctuation of readback output and decay of magnetization or erasure of recorded magnetization in the recording layer. A soft magnetic underlayer and a perpendicular recording layer are formed in specific order on the substrate of a magnetic disk. The soft magnetic underlayer has a triple-layered structure in which a domain control layer, including an anti-ferromagnetic layer, is sandwiched between two first and second soft magnetic layers. The thickness of the first and second soft magnetic layers (d, d) is between 25 nm and 150 nm and a ratio of d/dis within a range of 0.3 to 1.5. Accordingly, magnetic domains in the soft magnetic underlayer of a perpendicular magnetic recording medium can be controlled and magnetic domain wall motion can be inhibited.