Dependence of Angular Dispersion on Grain Size in Evaporated Permalloy Films

Permalloy films of nearly zero magnetostriction composition were evaporated in groups corresponding to two different thickness ranges. The mean grain size D was made to vary from 150 to 550 Å corresponding to different substrate temperatures. Angular dispersion α50 was found to increase with increas...

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Bibliographic Details
Published in:Journal of applied physics 1966-03, Vol.37 (3), p.1283-1284
Main Authors: West, F. G., Simmons, C. L.
Format: Article
Language:English
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Summary:Permalloy films of nearly zero magnetostriction composition were evaporated in groups corresponding to two different thickness ranges. The mean grain size D was made to vary from 150 to 550 Å corresponding to different substrate temperatures. Angular dispersion α50 was found to increase with increasing grain size; but the product of dispersion and anisotropy field, α50 Hk, was found to be nearly independent of grain size from about 200 to 550 Å. No dependence on film thickness t was observed. From ripple theory Hoffmann has predicted that α50 should be proportional to σ2D3/tHk, where σ is an average of the randomly varying torque resulting from the anisotropy energy in each grain. While the experimental results agree with the predicted dependence on Hk, the lack of dependence of α50 Hk on D and t requires modifications to the ripple theory. Possible modifications are discussed.
ISSN:0021-8979
1089-7550
DOI:10.1063/1.1708435