Dependence of magnetics, microstructures and recording properties on underlayer thickness in CoNiCr/Cr media

Author

Yogi, Tadashi ; Gorman, Grace L. ; Hwang, Cherngye ; Kakalec, Michael A. ; Lambert, Steven E.

Author_Institution

IBM Almaden Res. Center, San Jose, CA, USA

Volume

24

Issue

6

fYear

1988

fDate

11/1/1988 12:00:00 AM

Firstpage

2727

Lastpage

2729

Abstract

The effect of Cr underlayer thickness on the magnetic, microstructural, and recording properties of sputtered CoNiCr media is reported. Cr thickness was varied from 100 to 2000 Å while the magnetic layer was maintained in the range of 260-300 Å. Measurements using a vibrating sample magnetometer show a monotonic enhancement of coercivity from 600 to 1500 Oe with increasing Cr thickness. Media noise was measured as a function of transition density using a spectrum analyzer. The media noise power at 2400 flux changes per millimeter decreased by a factor of about 10 with the increase in Cr thickness. This reduction is accompanied by a reduction in the coercivity squareness and the development of granular features in CoNiCr grains growing on the columns of the Cr underlayer. These features are consistent with a reduction of exchange coupling among CoNiCr grains

Keywords

chromium; chromium alloys; cobalt alloys; coercive force; ferromagnetic properties of substances; magnetic recording; magnetic thin films; nickel alloys; sputtered coatings; storage media; 100 to 2000 Å; CoNiCr grains; Cr underlayer thickness; coercivity; exchange coupling; granular features; magnetic storage media; media noise power; microstructures; recording properties; sputtered CoNiCr media; transition density; Chromium; Coercive force; Density measurement; Magnetic noise; Magnetic properties; Magnetic recording; Magnetometers; Microstructure; Thickness measurement; Vibration measurement;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.92226

Filename

92226