Metamagnetism of Ferromagnetic Kondo Compound SmFe4P12

SmFe 4 P 12 is a novel ferromagnetic heavy fermion compound with a Curie temperature T c of 1.6 K. The electronic specific heat coefficient is 370 mJ/mol·K 2 . The magnetic susceptibility of La 1- x Sm x Fe 4 P 12 (0.6 ≤ x ≤0.85) with a paramagnetic ground state shows a broad maximum around 15 K. This phenomenon reminds us the case of CeRu 2 Si 2 which is in the boundary of itinerant and localized 4f-state. We measured the magnetization up to 42 T and found metamagnetic crossover at 22 T. The metamagnetism disappears with increasing temperature. Possible mechanism of the metamagnetism is discussed.