Intermediate-valence Tm: An exactly solvable impurity model

Abstract

We propose an exactly solvable model for valence fluctuations between two magnetic configurations. Most of the peculiar features of the magnetic properties of paramagnetic intermediate-valence Tm compounds are well described by the model. We calculate valence, specific heat, static magnetic susceptibilities, magnetization, and magnetoresistivity. We also include the resulting dynamical magnetic susceptibility. The results are in good qualitative agreement with experiment.