Thermally activated itinerant metamagnetic transition in LaFe11.7Si1.3 -: art. no. 212402

We have investigated the process of a metamagnetic transition (MT) between the ferromagnetic and paramagnetic states in the LaFe11.7Si1.3 compound, which has both giant magnetocaloric and large magnetovolume effects. The nucleation in MT, which indicates the coexistence of two phases, can be obviously activated by thermal fluctuation in the presence of magnetic fields. The experimental magnetization curves are well reproduced based on the itinerant metamagnetism theory considering thermal activation, and are largely different from the athermal MT. The critical nucleation volume for the phase transition approximates to 300 nm(3), and the surface energy to prevent MT is about 2x10(-4) J/m(2).