Structural and Magnetic Characteristics of Annealed Electrodeposited Permalloy Films

Abstract

Electrodeposited uniaxial Permalloy films 10 000 Å thick were annealed for 3 min at temperatures up to 400°C in an easy direction field greater than H_k. Dispersion, α₉₀, increases from 1.8° as plated to about 3.3° with annealing at 325°C. In the same temperature interval, skew and H_k remain unchanged. Above 325°C the magnetic properties change rapidly towards isotropic behavior. The onset of this effect is correlated with a large change in crystallite size. Transmission electron micrographs show a small increase in crystallite size D from 150 Å as‐plated to 500 Å for annealing at 325°C, and a rapid size increase thereafter. The data for the change in α₉₀ with D does not agree with theoretical predictions of Hoffmann; experimentally α₉₀ is found to be proportional to D^0.5 for annealing to 325°C.