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. 24, 2009
Filed:
Apr. 12, 2005
Hiroyuki Uwazumi, Nagano, JP;
Youichi Tei, Nagano, JP;
Kengo Kainuma, Nagano, JP;
Kazuhito Higuchi, Nagano, JP;
Akira Iso, Nagano, JP;
Hajime Kurihara, Nagano, JP;
Hiroyuki Uwazumi, Nagano, JP;
Youichi Tei, Nagano, JP;
Kengo Kainuma, Nagano, JP;
Kazuhito Higuchi, Nagano, JP;
Akira Iso, Nagano, JP;
Hajime Kurihara, Nagano, JP;
Abstract
A disk substrate for a perpendicular magnetic recording medium is, disclosed. The substrate exhibits sufficient productivity, serves the function of a soft magnetic backing layer of the perpendicular magnetic recording medium, and scarcely generates noise. A perpendicular magnetic recording medium using such a substrate also is disclosed. The disk substrate comprises at least a soft magnetic underlayer formed on a nonmagnetic base plate by means of an electroless plating method. The thermal expansion coefficient of the soft magnetic underlayer is larger than a thermal expansion coefficient of the nonmagnetic disk-shaped base plate. A saturation magnetostriction constant λs satisfies a relation λs≧−1×10.