Paramagnon picture of the low-temperature susceptibility of some intermediate-valence compounds

We show that the low-temperature susceptibility of Ce (In,0ex0exSn)₃ compounds has a quadratic temperature dependence with positive coefficient. We demonstrate that this behavior is well accounted for by a generalization to arbitrary band shapes of the paramagnon theory, which has been applied previously to liquid ³He. This result is relevant to the whole class of mixed-valence materials. We conclude that the previously proposed phenomenology that treats valence-fluctuation materials as heavy, nearly magnetic Fermi liquids finds further support in the present analysis.