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:
Mar. 25, 2014
Filed:
Feb. 13, 2012
Hiroaki Nemoto, Odawara, JP;
Ikuko Takekuma, Yokohama, JP;
Kimio Nakamura, Fujisawa, JP;
Junichi Sayama, Fujisawa, JP;
Hiroaki Nemoto, Odawara, JP;
Ikuko Takekuma, Yokohama, JP;
Kimio Nakamura, Fujisawa, JP;
Junichi Sayama, Fujisawa, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
Surface flatness of magnetic recording medium to which a magnetic recording layer made of L1FePt magnetic alloy thin film, with distance between a magnetic head and a magnetic recording medium sufficiently reduced. The magnetic recording layer includes: magnetic layers containing a magnetic alloy including Fe and Pt as principal materials; and one non-magnetic material selected from carbon, oxide and nitride. The first magnetic layer disposed closer to a substrate has a granular structure in which magnetic alloy grains including FePt alloy as the principal material are separated from grain boundaries including the non-magnetic material as the principal material. The second magnetic layer disposed closer to the surface than the first magnetic layer is fabricated so as to have a homogeneous structure in which an FePt alloy and the non-magnetic material are mixed in a state finer than diameters of the FePt magnetic alloy grains in the first magnetic layer.