Inelastic neutron scattering study on low-energy excitations of the heavy-fermion superconductor PrOs4Sb12

Abstract Low-energy magnetic excitations in single crystals of the heavy-fermion superconductor PrOs 4 Sb 12 have been studied by inelastic neutron scattering. The clear softening of excitations at a wave vector Q = ( 1 , 0 , 0 ) , which is the same as the modulation vector of the field-induced antiferro-quadrupolar ordering, and the intensity analyses of excitations directly evidence that the nonmagnetic quadrupolar fluctuations are dominant in this system. Furthermore, the narrowing of the linewidths of the excitations in the superconducting phase indicates the close connection between the superconductivity and the excitations. The preliminary data under magnetic fields are also presented.