Intermultiplet Transitions In Filled Skutterudite Smfe4p12

The intermultiplet transitions in filled skutterudite SmFe4P12 are studied by magnetization and time-of-flight inelastic neutron scattering experiments. In neutron scattering experiments by using high energy neutrons for reducing huge neutron absorption of natural Sm, a small inelastic peak has been observed around similar to 80 meV at low temperature. The scattering vector dependence of intensity of this peak agrees with the theoretical inelastic structure factor for the intermultiplet transition from the ground J = 5/2 multiplet to the excited J = 7/2 multiplet in Sm3+ ion. Interestingly, the energy splitting is much smaller than the free Sm3+ ion value. This is also comparable with that estimated by the inverse magnetic susceptibility. This large reduction of the energy splitting might be due to the strong c-f mixing in SmFe4P12.