First evidence for a Sm3+-type contribution to the magnetic form factor in the quasielastic spectral response of intermediate valence SmB6

The momentum-transfer dependence of the magnetic form factor associated with the quasielastic spectral component in the dynamic magnetic response of intermediate valence SmB 6 has been measured using inelastic neutron scattering on a double-isotope ( 154 Sm, 11 B) single crystal. The experimental dependence differs qualitatively from those obtained earlier for the inelastic signals, as well as from the field-induced magnetic form factor of SmB 6 obtained by polarized neutron diffraction. This observation is interpreted by specifically considering the Curie-type contributions to the dynamic susceptibility, which arise from the mixing of 4 f 5 and 4 f 6 J -multiplets into the intermediate valence state wavefunction.