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:
May. 29, 1990
Filed:
Mar. 22, 1988
Bangalore R Natarajan, Cupertino, CA (US);
Robert G Walmsley, Palo Alto, CA (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A magnetic thin film materials system (10, 10') is provided, comprising a thin magnetic film (16) formed on a non-magnetic underlayer (14) formed on a substrate (12). In particular, the magnetic film comprises a composition consisting essentially of CoCrPt, with Cr ranging from about 10 to 20 at %, Pt ranging from about 1 to 20 at % and the balance Co. The underlayer consists essentially of chromium. The magnetic layer ranges in thickness from about 200 to 1,200 .ANG., while the non-magnetic underlayer ranges in thickness from about 500 to 5,000 .ANG.. The platinum control film coercivity, while chromium provides corrosion resistance. In addition, chromium controls the recorded magnetic transition noise properties. An increase in Cr content in these alloys beyond about 10 at % increases the corrosion resistance and unexpectedly lowers the transition noise significantly. Coercivities of from about 500 to greater than 2,000 Oe and magnetization-thickness products from 1 to 6.times.10.sup.-3 emu/cm.sup.2 are attained by the magnetic recording system of the invention. A thin carbon wear layer (18) (about 200 to 800 .ANG.) is provided over the magnetic layer, with an optional thin chromium adhesion layer (20) (0 to about 500 .ANG.) interposed therebetween.