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. 11, 2010
Filed:
Mar. 03, 2005
Yoshihiko Minachi, Tokyo, JP;
Noboru Ito, Tokyo, JP;
Junichi Nagaoka, Tokyo, JP;
Shunsuke Kurasawa, Tokyo, JP;
Taku Murase, Tokyo, JP;
Yoshihiko Minachi, Tokyo, JP;
Noboru Ito, Tokyo, JP;
Junichi Nagaoka, Tokyo, JP;
Shunsuke Kurasawa, Tokyo, JP;
Taku Murase, Tokyo, JP;
TDK Corporation, Tokyo, JP;
Abstract
W-type ferrite has improved magnetic properties, in particular, coercive force. A high coercive force (HcJ) and a high residual magnetic flux density (Br) can be simultaneously attained by a ferrite magnetic material comprising an oxide having a composition wherein metal elements Sr, Ba and Fe in total have a composition ratio represented by the formula SrBaFeFein which 0.03 ≦x≦0.80, 1.1≦a≦2.4, and 12.3≦b≦16.1. The ferrite magnetic material can form any of a ferrite sintered magnet, a ferrite magnet powder, a bonded magnet as a ferrite magnet powder dispersed in a resin, and a magnetic recording medium as a film-type magnetic phase. As for the ferrite sintered magnet, there can be attained a fine sintered structure that has a mean grain size of 0.6 μm or less.