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. 07, 2019
Filed:
Nov. 28, 2016
Showa Denko K.k., Tokyo, JP;
Ken Inoue, Chiba, JP;
Kota Hasegawa, Chiba, JP;
SHOWA DENKO K.K., Tokyo, JP;
Abstract
A magnetic recording medium includes a non-magnetic substrate on which at least a soft magnetic underlayer, an orientation control layer, a perpendicular magnetic layer, and a protective layer are disposed. The perpendicular magnetic layer includes first to fourth magnetic layers. A first exchange coupling control layer is disposed between the first magnetic layer and the second magnetic layer. A second exchange coupling control layer is disposed between the second magnetic layer and the third magnetic layer. Following relations are satisfied where Kuis a magnetic anisotropic constant of an i-th magnetic layer, Msis a saturation magnetization of the i-th magnetic layer, and tis a film thickness of the i-th magnetic layer, Ku>Ku, Ku>Ku, Ms×t>Ms×t, Ms×t>Ms×t, Ku<Ku, and Ms×t<Ms×t.