A large thermal elasticity of the ordered FeRh alloy film with sharp magnetic transition

Thermal elasticity and electrical resistivity with the magnetic phase transition were studied in FeRh alloy films prepared by ion-beam sputtering and subjected to post-annealing. Fe_49.7Rh_50.3 and Fe_48.9Rh_51.1 films deposited on conventional glass substrate and subjected to post-annealing at 600°C for 90 min, respectively. Both films show a considerably sharp transition. In particular, Fe_49.7Rh_50.3 film exhibits small thermal hysteresis of about 20°C width, which is only about 2 times over than that of bulk. Furthermore, a large abrupt thermal strain over 2×10^-3 was observed with the magnetic transition. These results indicate that strictly controlled an equiatomic composition is an effective way to obtain the FeRh film with abrupt magnetic phase transition under low temperature and short time annealing.