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:
Oct. 20, 1998
Filed:
Jun. 27, 1996
Masato Kobayashi, Tokyo, JP;
Keiji Moroishi, Yamanashi, JP;
Jun-ichi Horikawa, Yamanashi, JP;
Osamu Nozawa, Tokyo, JP;
Hoya Corporation, Tokyo, JP;
Abstract
A magnetic recording medium comprising a non-magnetic underlayer and a CoPt magnetic layer provided on a substrate in this order wherein the non-magnetic underlayer comprises one or more non-magnetic layers, one of the non-magnetic layers which is in contact with the CoPt magnetic layer consists mainly of Cr and Mo, and difference (d.sub.(002) -d.sub.(110)) obtained by subtracting a crystalline lattice spacing of bcc (110) faces in the non-magnetic layer consisting mainly of Cr and Mo from a crystalline lattice spacing of hcp (002) faces in the magnetic layer falls within a range of from 0.002 to 0.032 .ANG., which shows a high magnetic coercive force and square ratio and a low medium noise, and a method for producing the magnetic recording medium mentioned above wherein at least the non-magnetic layer consisting mainly of Cr and Mo and the CoPt magnetic layer are formed by a sputtering technique using a substrate heating temperature within a range of 250.degree. to 425.degree. C. and an Ar gas pressure within a range of 0.5 to 10 mTorr.