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:
Jun. 27, 1989
Filed:
Aug. 24, 1987
Tomoyuki Ohno, Kokubunji, JP;
Yoshihiro Shiroishi, Hachioji, JP;
Sadao Hishiyama, Sayama, JP;
Hiroyuki Suzuki, Kawasaki, JP;
Takaaki Shirakura, Chigasaki, JP;
Shinya Matsuoka, Odawara, JP;
Makoto Sano, Kanagawa, JP;
Takao Nakamura, Yokohama, JP;
Kazumasa Takagi, Tokyo, JP;
Tokuumi Fukazawa, Tachikawa, JP;
Kenzo Susa, Tokyo, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A magnetic recording medium having a magnetic film formed on a substrate directly or through an underlayer from an alloy containing Co as a principal component. The central line average surface roughness Ra and maximum surface roughness Rmax of the magnetic film in a direction perpendicular to the direction of magnetic recording are selected so as to fall within the ranges of 1 nm.ltoreq.Ra.ltoreq.20 nm and Rmax.ltoreq.25 Ra, respectively, and the in-plane magnetic anisotropy energy Ku of the magnetic film is selected to fall within the range of 0.ltoreq.Ku.ltoreq.8.times.10.sup.5 erg/cm.sup.3. Thus, it is possible to minimize the value of modulation which represents the degree of variation of read output on the same circumference of a magnetic disk. It is also possible to reduce the noise generated in read and write operations by forming the magnetic film so as have no crystallographic orientation.