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:
Aug. 24, 2010
Filed:
Aug. 28, 2007
Shin-ichi Ohkoshi, Tokyo, JP;
Shunsuke Sakurai, Tokyo, JP;
Shiro Kuroki, Saito, JP;
Kimitaka Sato, Honjyo, JP;
Shinya Sasaki, Okayama, JP;
Shin-ichi Ohkoshi, Tokyo, JP;
Shunsuke Sakurai, Tokyo, JP;
Shiro Kuroki, Saito, JP;
Kimitaka Sato, Honjyo, JP;
Shinya Sasaki, Okayama, JP;
The University of Tokyo, Tokyo, JP;
Dowa Electronics Materials Co., Ltd., Tokyo, JP;
Abstract
A magnetic material is provided that has an iron oxide phase whose principal phase is a crystal of a structure which has the same space group as ε-FeOcrystal and in which Al is substituted for a portion of the Fe sites of the ε-FeOcrystal. The molar ratio of Al to Fe in the iron oxide phase, when expressed as Al:Fe=x:(2−x), satisfies 0≦x≦1. The value of x is preferably in the range of 0.3 to 0.7. The average particle diameter of the powder determined from a TEM image is preferably 5 to 200 nm, more preferably 10 to 100 nm. The magnetic material has very high practical value because it enables the extremely high coercive force Hc of the ε-FeOcrystal to be regulated to a level enabling utilization in magnetic recording medium and various other applications. The magnetic powder can be produced by a method combining the reverse micelle method and the sol-gel method.