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

Abstract

We show that the low-temperature susceptibility of Ce ${\mathrm{}(\mathrm{I}\mathrm{n},\mathrm{S}\mathrm{n})\mathrm{}}_3$ 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 ${}_{}{}^3{}_{}{}^{}\mathrm{He}$. 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.