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:
Jan. 27, 2009
Filed:
May. 24, 2005
Hoa Van DO, Fremont, CA (US);
Bernd Heinz, San Jose, CA (US);
Yoshihiro Ikeda, San Jose, CA (US);
Kentaro Takano, San Jose, CA (US);
Min Xiao, San Jose, CA (US);
Hoa Van Do, Fremont, CA (US);
Bernd Heinz, San Jose, CA (US);
Yoshihiro Ikeda, San Jose, CA (US);
Kentaro Takano, San Jose, CA (US);
Min Xiao, San Jose, CA (US);
Hitachi Global Storage Technologies Netherlands B.V., Amsterdam, NL;
Abstract
A perpendicular magnetic recording disk has an improved recording layer of a granular CoPtCr-based ferromagnetic alloy with inter-granular material made up of one or more oxides of Cr and one or more oxides of one or more of a segregant of Si, Ta, Ti, B, Nb or Hf, wherein the amount of oxygen present in the recording layer is greater than about 22 atomic percent and less than about 35 atomic percent. The amount of oxygen in the recording layer is substantially greater than the amount required for the stoichiometric oxide or oxides of the segregant or segregants, and a substantial portion of the oxygen present in the recording layer is present in the inter-granular material. The recording layer exhibits high signal-to-noise ratio (SNR), a coercivity Hgreater than about 5000 Oe and a nucleation field Hgreater (more negative) than about −1500 Oe.