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. 14, 1984
Filed:
Sep. 23, 1982
Applicant:
Inventors:
Fumio Togawa, Ohtsu, JP;
Shigeo Aoyama, Ibaraki, JP;
Assignee:
Hitachi Maxell, Ltd., Osaka, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01F / ;
U.S. Cl.
CPC ...
428329 ; 428339 ; 428403 ; 428457 ; 428694 ; 428900 ;
Abstract
An improved magnetic recording medium suitable for high density recording is disclosed, which has a squareness ratio in the vertical direction of 0.6 or more and an orientation ratio (squareness ratio in the vertical direction/squareness ratio in the lengthwise direction) of 0.7 or more, prepared from acicular magnetic iron oxide particles having crystalline magnetic anisotropy and a ratio of Fe.sup.2+ /Fe.sup.3+ of 0.05 or less uniformly cobalt-doped, the particles having preferably a particle size of 0.3.mu. or less and an axial ratio of 6 to 10.