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:
Oct. 12, 2004
Filed:
Apr. 25, 2002
Junichi Sato, Nara, JP;
Kosuke Watanabe, Yao, JP;
Kunio Kojima, Nabari, JP;
Hiroyuki Katayama, Nara, JP;
Hiroshi Fuji, Soraku-gun, JP;
Kenji Ohta, Kitakatsuragi-gun, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
A magnetic recording medium, which includes a substrate and an amorphous magnetic layer, made of an amorphous magnetic material, for magnetic recording of data, is provided with an underlayer between the substrate and the amorphous magnetic layer, the underlayer being made of amorphous metal element, and having a mean thickness of 10 nm or less. In this manner, movement of magnetic domain walls of the amorphous magnetic layer is effectively limited by minute irregularities on a surface of the underlayer. This realizes a stable formation of a minute recording mark. This realizes recording having a sufficient signal quality, even when the high-density recording is performed by forming such a minute recording mark that a shortest length of the recording mark is less than 100 nm. Moreover, this allows the magnetic recording medium to have a simplified layer structure. Further, a magnetic recording apparatus magnetically records data onto a magnetic recording medium having the above arrangement, by heating a portion of the magnetic layer by radiating a light beam locally, and by applying a magnetic field on at least part of the portion of the magnetic layer on which the light beam is radiated. This provides a magnetic recording apparatus for high-density recording.