Deposition of Fe-Pd Ferromagnetic Shape Memory Alloy Thin Films by Sputtering and Their Shape Memory Behavior

摘要

The purposes of this study are primarily to obtain basic knowledge of the fabrication of Fe-Pd ferromagnetic shape memory (SM) thin films and to investigate the effect of Pd content and thickness on the martensitic transformation behavior. Fe-Pd films were deposited onto fused quartz substrates by dual source sputtering. The crystal structures of as-sputtered films of Fe-28～30at%Pd and Fe-30～32at%Pd alloys were found to be bcc and fee, respectively. It was observed that the crystal structure of Fe-28～30at%Pd films changed into a structure containing a fct phase after annealing at 900°C for 60 min followed by iced water quenching. The Pd content region where annealed films contain a fct structure tends to shift higher Pd with increasing film thickness. Annealed films containing fct phase underwent a thermoelastic fcc-to-fct martensitic transformation. The M_s temperature of films containing 28.5～30.0at% Pd was higher than RT, and it became lower with increasing Pd content. Fe-Pd films fabricated on thin Si substrates were found to show cyclic SM behavior under a constant magnetic bias force when temperature was changed repeatedly.