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:
Jul. 15, 2008
Filed:
Oct. 16, 2003
Hiroshi Yamamoto, Kanagawa, JP;
Natsuki Wakamura, Kanagawa, JP;
Naoki Yoshida, Kanagawa, JP;
Meiji University Legal Person, Tokyo, JP;
Abstract
Provided is a magnetic material with excellent magnetic properties to be used for recording media, which contains small ratio of superparamagnetic fine particles while maintaining high coercivity. It is spinel ferrimagnetic particles, a composition equation of which when prepared is (CoO)(NiO)(MO).n/2(FeO) (M is a bivalent metal except Co and Ni) and a value of n (molar ratio)=Fe/(Co+Ni+Zn) is 2.0<n<3.0, which is larger than stoichiometric amount (n=2) of a spinel ferrite and less than that of 1.5 times, and values of x, y satisfy 0≦x<0.5, 0≦y<0.5, 0<x+y<0.5, wherein, also, superparamagnetic fine particles contained in the spinel ferrimagnetic particles is 5% by mass or less.