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. 25, 1987
Filed:
Aug. 27, 1984
Applicant:
Inventors:
Assignee:
TDK Corporation, Tokyo, JP;
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
428212 ; 427128 ; 427131 ; 428216 ; 428328 ; 428329 ; 428694 ; 428215 ; 428900 ;
Abstract
A magnetic recording medium comprising a substrate and magnetic recording double-layers formed on the substrate, wherein the magnetic material of the magnetic recording under-layer is composed essentially of an alloy or metal magnetic powder having a specific surface area of at most 30 m.sup.2 /g as measured by BET method, and the magnetic material of the magnetic recording top-layer is composed essentially of an iron oxide or Co-adsorbed iron oxide powder having a specific surface area of at least 25 m.sup.2 /g as measured by BET method.