Fe-Pd ferromagnetic shape memory alloy thin films made by dual source DC magnetron sputtering

Abstract

Fe-Pd films have been deposited onto fused quartz substrates using a dual source dc magnetron sputtering apparatus, equipped with two independent targets of pure Fe and Pd. The Pd content of deposited films can be controlled with an accuracy of 1 at%Pd by varying the power for the Pd target at constant power for the Fe target. Fe-Pd films containing about 29 at%Pd show a fct structure after annealing at 900°C followed by quenching into iced water. These films underwent a thermoelastic fcc-to-fct martensitic transformation and the fct-phase region, where the fct phase is present at room temperature in the annealed films, has a tendency of shifting toward higher Pd content with increasing film thickness. This thickness effect is attributed to the difference in internal stress created during annealing. The martensite start temperature (Ms) of films containing 28.5-30.0 at%Pd was higher than room temperature, and it became lower with increasing Pd content. When Fe-30at%Pd films were separated from the quartz substrate, they showed shape memory behavior upon heating after deformation.