Aging and stabilization of permalloy films

The aging characteristics of zero magnetostrictive thin-film Permalloy samples with a variety of impurities have been examined in the range from 60 to 90°C. Vacuum evaporated samples from three different sources, some with cobalt, and five different kinds of electrodeposited samples, some containing large amounts of phosphorus or sulfur, have been used. The changes in anisotropy field H
k
and dispersion α
q
on aging in a saturating hard axis field were dependent on the method of preparation of the films and their impurity content. However, the aging characteristics became independent of the source of the film and independent of the impurity present after a suitable stabilization anneal. No changes in M
s
or magnetostriction were observable during aging. The aging behavior of all of these films is qualitatively consistent with the model previously proposed for the effect of sulfur on the aging kinetics.