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. 26, 2005
Filed:
Feb. 05, 2003
Yoshio Takahashi, Koganei, JP;
Yotsuo Yahisa, Odawara, JP;
Yoshiyuki Hirayama, Kokubunji, JP;
Hitachi Global Storage Technologies Japan, Ltd., Kanagawa-ken, JP;
Abstract
Disclosed is a magnetic recording medium and a method for manufacturing the same to provide a magnetic recording medium reducing medium noise and having excellent thermal stability. The magnetic recording medium includes a substantially amorphous seed layer and a polycrystal underlayer made of crystal grains having a substantially columnar structure, the polycrystal underlayer contacting thereto. In a boundary between the seed layer and the underlayer, fine grooves having a period up to as large as the magnetic layer crystal grain diameter are formed in the disc circumferential direction. Accordingly, the magnetic recording medium is allowed to have a grain shape with a value obtained by dividing the average grain diameter for the disc circumferential direction by the average grain diameter for the disc radial direction of no less than 0.5 and no more than 0.9, thus achieving simultaneously reduction of the medium noise and thermal stability.