DocumentCode :
822702
Title :
Dependence of magnetic media noise on ultra-thin Cr underlayer thickness
Author :
Johnson, Kenneth E. ; Kim, Myong R. ; Guruswamy, Sivaraman
Author_Institution :
IBM, Rochester, MN, USA
Volume :
28
Issue :
5
fYear :
1992
fDate :
9/1/1992 12:00:00 AM
Firstpage :
3099
Lastpage :
3101
Abstract :
Magnetic films on Cr underlayers of thicknesses below 100 Å show an unexpected drop in media noise. Magnetic interactions as measured by coercive squareness and δM are also low. However, the microstructure of the films gives no evidence that physical segregation is the mechanism of exchange decoupling, as is the case for underlayers above 500 Å. It is suggested from diffuse electron diffraction patterns, the theory of heterogeneous nucleation applied to early stages of thin-film formation, and increased Ms values for the thin Cr cases that enhanced elemental segregation to the grain boundaries is occurring due to larger misorientation of grains. Elemental segregation gives rise to the low noise and decreased interactions. As the Cr underlayer increases in thickness, preferred columnar growth takes over and eventually results in physically segregated grains, which becomes the source of decoupling and noise reduction. In between the extremes, noise maximizes between 200 Å and 600 Å
Keywords :
chromium; coercive force; grain boundary segregation; magnetic recording; magnetic storage; magnetic thin films; noise; storage media; 25 to 1300 Å; Cr underlayers; coercive squareness; columnar growth; diffuse electron diffraction patterns; elemental segregation; exchange decoupling; grain boundaries; heterogeneous nucleation; high density magnetic recording; magnetic media noise; microstructure; noise reduction; thin film storage media; thin-film formation; ultrathin underlayer thickness; Chromium; Coercive force; Magnetic films; Magnetic noise; Magnetic properties; Magnetic separation; Microstructure; Noise reduction; Scanning electron microscopy; Sputtering;
fLanguage :
English
Journal_Title :
Magnetics, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9464
Type :
jour
DOI :
10.1109/20.179725
Filename :
179725
Link To Document :
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