Dynamic magnetic susceptibilities of valence-fluctuation Ce compounds

We have computed dynamic susceptibilities of valence-fluctuating Ce compunds for temperatures between 0.01 and 40 T0, where T0 is the position of the many-body ‘‘Kondo resonance’’ in the 4f density of states. Our calculations reproduce several results seen in neutron scattering and nuclear-magnetic-resonance experiments: (i) nonmonotonic behavior of the magnetic relaxation rate, (ii) non-Lorentzian behavior of the dynamic susceptibility for low temperatures, and (iii) high-temperature T1/2 behavior of the magnetic relaxation rate. Most of the magnetic relaxation data for valence-fluctuating Ce compunds are consistent with the Kondo resonance picture which has been applied successfully previously to thermodynamic and high-energy spectroscopy data.