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Proceedings Paper

Uniformity of radial and circumferential orientation ratio of particulate disks
Author(s): Walter Crooks; Dan Crump; Leo Liclican
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Paper Abstract

In magnetic recording on hard disks, coated with particulate media, the maietic panicles are oriented circumferentially to provide a higher signal amplitude for the read/write head. The degree of anisotropy is termed the orientation ratio. It is the value of the magnetic remanence measured in the easy axis direction or circumferential direction, divided by the rnaietic remanence measured in the hard axis direction or radial direction. It is preferred that this ratio he uniform from the inner-most recording track of the disk (ID) to the outermost recording track of the disk (01)). Additionally, it is preferred that this ratio be uniform circumlerentially around the disk surface. Magnetic performance in terms of uniform signal modulation is more satisfactory when the orientation ratio is uniform radially and circumlerentially compared to when this ratio varies someway in either or both of these directions. j\ nondestructive optical technique, which allows the radial and circumferential orientation uniformity to be rapidly measured on a disk after coating application and orientation, is described. The methods make use of a Cross Polarizing Microscope. This rapid measuring technique allows parameters to be changed quickly, should the orientation ratio he nonuniform in any way during disk development. This convenient method ensures that disks tested at sinJe disk test do not tini because of particle orientation problems.

Paper Details

Date Published: 1 August 1990
PDF: 1258 pages
Proc. SPIE 1248, Storage and Retrieval Systems and Applications, (1 August 1990); doi: 10.1117/12.19634
Show Author Affiliations
Walter Crooks, IBM Corp. (United States)
Dan Crump, IBM Corp. (United States)
Leo Liclican, IBM Corp. (United States)


Published in SPIE Proceedings Vol. 1248:
Storage and Retrieval Systems and Applications
David H. Davies; Han-Ping D. Shieh, Editor(s)

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