Angular Dependence of Magnetic Annealing Effects in Permalloy Base Films

Abstract

Attempts have been made to interpret magnetic annealing effects by assuming that the uniaxial anisotropy is caused by a directional order of local atomic configurations. By studying both evaporated and electroplated films, it is found that during an anneal the number of such elementary anisotropy sources is conserved. The angular dependence of magnetic annealing effects can be described by assuming a reorder of elementary anisotropy sources parallel to the magnetization at a rate independent of the magnetization direction. In the absence of a physical model describing the kinetics of reorder, it is shown how experimental values of the anisotropy field measured during hard-axis anneals can be used to predict for any annealing direction the changes in anisotropy field, skew, and coercivity. Changes in angular dispersion were also studied but could not be explained satisfactorily. The variations of all main film parameters are found to be reversible during subsequent easy-axis anneals, and the recovery of the anisotropy field during such an anneal can be used to predict the recovery of all other parameters. © 1968 IEEE. All Rights Reserved.