Collective Magnetic Order and Intermediate Valence in the Anderson Model

Abstract

AbstractThe question of the coexistence of long range magnetic order and intermediate valence is investigated using the periodic Anderson model. The average occupation nf of the relatively well localized 4f level and the corresponding magnetization mf are selfconsistently calculated keeping the total number of electrons N per lattice site fixed. The Curie temperature TC is determined following the temperature variation of mf. The behaviour of TC as a function of the position of the localized 4f level Ef for a constant Bloch band width W and as a function of W for a constant Ef are studied for different values of N. The results are interpreted in terms of the interplay between the relative occupation of the f‐level and the conduction band and the fluctuations caused by the hybridization. Similarities with experimental results are pointed out. A phase diagram is constructed which indicates the constellations of model parameters which permit long range magnetic order.