Giant volume magnetostriction due to the itinerant electron metamagnetic transition in La(Fe-Si)13 compounds

Ferromagnetic La(Fe_xSi_1-x)₁₃ compounds with x⩾0.87 show an itinerant metamagnetic transition above the Curie temperature T_c. Since a large volume change of about 1.5% is caused by the transition, the present compounds have a possibility for practical applications as giant magnetostrictive materials. To adjust T_c around room temperature, the effect of the substitution by other magnetic elements on the Curie temperature was examined. The Curie temperature of La(Fe_0.88Co_ySi_0.12-y)₁₃ compounds increases with increasing y and the itinerant electron metamagnetic transition appears above T_c. For y=0.03 and 0.04, a huge volume change of 0.6~0.9%, or a linear change of 0.2~0.3%, due to the itinerant metamagnetic transition is observed around 250 K