Some Observations on Evaporated Permalloy Films

Experimental study of the chemical and physical characteristics of evaporated Permalloy films have been carried out. Observations regarding chemical homogeneity, applied strains, and magnetic annealing are reported. Results showed that chemical heterogeneity could exist in such films; possible effects of heterogeneity are speculated. Longitudinal compressive strains, when applied to a magnetostrictive film, could markedly increase its magnetization reversal speed and change its preferred direction. Magnetic annealing of 75%‐Ni films at 300°C in a transverse field irreversibly changed the films' preferred directions by 90°, reducing the ${\mathrm{H\prime }}_k\mathrm{s}$ to 3.0 oe, with maximum variations of ±0.5 oe.