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:
Nov. 04, 1980
Filed:
Aug. 18, 1977
Applicant:
Inventors:
Seizi Hattori, Ibaragi, JP;
Koichi Makino, Yokohama, JP;
Takehiko Nakagawa, Kawasaki, JP;
Masayoshi Shinohara, Kokubunji, JP;
Assignee:
Fujitsu Limited, , JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
427130 ; 2041 / ; 252 6255 ; 252 6256 ; 252 6257 ; 252 6258 ; 252 6259 ; 252 626 ; 427132 ; 428900 ;
Abstract
A thin film of ferrite for use as a magnetic recording medium includes (a) Cu and Ti or (b) Cu, Ti and Co. The inclusion of Ti extends upwards the upper limit of the range of temperature for reducing .alpha.-Fe.sub.2 O.sub.3 to Fe.sub.3 O.sub.4, whereas the inclusion of Cu extends downwards the lower limit of this range. Further, the inclusion of both Ti and Cu enables the stable production of .gamma.-Fe.sub.2 O.sub.3 over a wide range of temperature for oxidizing Fe.sub.3 O.sub.4 to said .gamma.-Fe.sub.2 O.sub.3. The inclusion of Co improves the magnetic properties of the ferrite.