Anisotropy dispersion measurements in permalloy thin films

Abstract

Studies of the relationship between structure and properties of annealed permalloy thin films carried out by Horowitz and Rudee and supported by the work of Landler indicate substantial disagreement with the predictions of Hoffmann's linear theory of ripple. Small area dispersion measurements by Fujii et. al. indicate agreement with Hoffmann's theory. The present work deals with small-area Faraday effect measurement of dispersion using the hard-axis fallback technique, applied to films preannealed to obtain a stable structure and then isothermally annealed at lower temperatures to enable the determination of the relationship of anisotropy field to dispersion. In agreement with the observations of Dove and Long, the effects of interactions between film regions are found to be vitally important in the Interpretation of the measurements. The results substantiate Horowitz's conclusion that the dispersion and anisotropy field parameters are related.