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. 08, 2014
Filed:
Nov. 02, 2012
Fuji Electric Co., Ltd., Kawasaki, JP;
National University Corporation Tohoku University, Sendai, JP;
Osamu Kitakami, Sendai, JP;
Yutaka Shimada, Sendai, JP;
Satoshi Okamoto, Sendai, JP;
Takehito Shimatsu, Natori, JP;
Hajime Aoi, Sendai, JP;
Hiroaki Muraoka, Sendai, JP;
Yoshihisa Nakamura, Sendai, JP;
Hiroyuki Uwazumi, Shinagawa-ku, JP;
Tadaaki Oikawa, Yokosuka, JP;
Abstract
A perpendicular magnetic recording medium according to which both the thermal stability of the magnetization is good and writing with a magnetic head is easy, and moreover the SNR is improved. In the case of a perpendicular magnetic recording medium comprising a nonmagnetic substrate (), and at least a nonmagnetic underlayer (), a magnetic recording layer (), and a protective layer () formed in this order on the nonmagnetic substrate (), the magnetic recording layer () comprises a low Kregion () layer having a perpendicular magnetic anisotropy constant (Kvalue) of not more than 1×10erg/cm, and a high Kregion () layer having a Kvalue of at least 1×10erg/cm. Moreover, the magnetic recording layer () is made to have therein nonmagnetic grain boundaries that contain a nonmagnetic oxide and magnetically isolate crystal grains, which are made of a ferromagnetic metal, from one another.