Evaluation of Annealing Effect on Sputtered FePd Magnetostrictive Film using MEMS Cantilever

Abstract

Effect of annealing on magnetostriction of sputtered Fe₆₀Pd₄₀ film was evaluated using MEMS cantilevers with multi-layer structure of FePd (2 µm) / SiO₂ (0.1 µm) / Si (50 µm). Magnetostrictive effect, which was about 45 ppm before annealing, increased 1.5-3 times after annealing at 350-450℃ for 30 min. In contrast, magnetostriction along the cantilever was lost when annealing at 500℃. The FePd film surface was highly oriented to fct <111)> and fcc <111> planes. In addition to the <111> orientation, in-plane crystal phase was oriented to fct <220> and fcc <220> planes. After annealing, surface orientated fct <111> plane increased with icreaseing annealing temperature, in spite of the magnetostoriction loss at 500℃, indicating that the fct <111> orientation has no effect on magnetostriction. In-plane fct <220> plane crystallization advanced by 400℃ annealing, and the orientation to fct <220> decreased by 500℃annealing, which were same tendency of the increase and decrease of the magnetstriction.