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. 26, 2005
Filed:
Dec. 09, 2002
Tadaaki Oikawa, Nagano, JP;
Hiroyuki Uwazumi, Nagano, JP;
Shunji Takenoiri, Nagano, JP;
Miyabi Nakamura, Ibaragi, JP;
Tadaaki Oikawa, Nagano, JP;
Hiroyuki Uwazumi, Nagano, JP;
Shunji Takenoiri, Nagano, JP;
Miyabi Nakamura, Ibaragi, JP;
Fuji Electric Co., Ld., , JP;
Abstract
A perpendicular magnetic recording medium has a nonmagnetic substrate, a nonmagnetic underlayer, a magnetic layer, a protective film, and a liquid lubrication layer sequentially laminated on the substrate. The nonmagnetic layer is composed of a metal or alloy having a hcp crystal structure. The magnetic recording layer consists of ferromagnetic crystal grains and a nonmagnetic grain boundary phase mainly composed of an oxide surrounding the grains. A seed layer of a metal or alloy having a fcc crystal structure can be provided under the nonmagnetic underlayer, and a nonmagnetic alignment control layer can be provided under the seed layer. The recording medium can provide high output and low noise by improving the alignment of the magnetic recording layer, reducing the initial growth layer in the magnetic recording layer, and minimizing the grain size of the magnetic recording layer.