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 Hk. Dispersion, α90, increases from 1.8° as plated to about 3.3° with annealing at 325°C. In the same temperature interval, skew and Hk 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 D0.5 for annealing to 325°C.

The Influence of Annealing on the Structure of Polycrystalline Permalloy Thin Films

“…On the one hand, a number of quantitative statements in which granular structure and the mean crystallite size play a dominant, role, have been derived theoretically (e. g. [l]). On the other hand, it has been established experimentally [2] that, although this role is certainly essential, some theoretical statements [l] are not in complete accordance with the measuring data. It is to be expected, therefore, that a number of simplifying assumptions underlying the theoretical deductions could be not satisfied thus causing the afore-mentioned divergences.…”