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. 20, 2008
Filed:
Oct. 29, 2004
Ryoko Araki, Tokyo, JP;
Yoshio Takahashi, Tokyo, JP;
Ryoko Araki, Tokyo, JP;
Yoshio Takahashi, Tokyo, JP;
Hitachi Global Storage Technologies Netherlands B.V., Amsterdam, NL;
Abstract
A distribution of grain boundaries in a magnetic recording medium having a granular structure is reduced so that the magnetic recording medium with a high medium signal-to-noise ratio is provided. According to one embodiment, in an underlayer composed of grains each having a generally columnar structure and in a magnetic recording layer composed of magnetic crystal grains each having a generally columnar structure and grain boundaries, a grain size Dm of the magnetic recording layer and a grain size Du of each of the underlayer crystal grains are determined to satisfy a relationship represented by 0.8×Du≦Dm<Du and a standardized grain boundary distribution obtained by dividing the standardized deviation of the distribution of the grain boundaries by an average grain boundary width is adjusted to about 0.4 or less.