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. 29, 1980
Filed:
Mar. 02, 1977
Seizi Hattori, Nishiibaragi, JP;
Takehiko Nakagawa, Kawasaki, JP;
Kazuo Kobayashi, Koza, JP;
Koichi Makino, Yokohama, JP;
Wakatake Matsuda, Zama, JP;
Fujitsu Limited, both of, JP;
Nippon Telegraph and Telephone Public Corporation, both of, JP;
Abstract
A thin film of ferrite for use as a magnetic recording medium includes up to ten atomic percent of Nb based on the total number of metallic atoms in the ferrite film. This thin film of ferrite further includes up to fifteen atomic percent of Cu in addition to the Nb. The inclusion of Nb improves the squareness ratio and the coercive force of the recording medium, and also enlarges the temperature range of reduction from .alpha. -Fe.sub.2 O.sub.3 to one of the ferrites, i.e. Fe.sub.3 O.sub.4. The inclusion of Cu lowers the reduction temperature below 300.degree. C. According to the invention, a magnetic recording medium exhibiting excellent required properties, such as a high coercive force and a high squareness ratio, can be produced by a reliable process.