On the absence of magnetic order in intermediate valence compounds

We study the mechanism by which the magnetic order is suppressed in intermediate valence compounds. By a diagrammatic perturbation theory in the hybridization interaction, the effective inter-site exchange interaction is derived for the periodic Anderson model. The result includes the effect of charge fluctuations and is valid for arbitrary position of the local electron level relative to the Fermi level. It is shown that the intersite interaction is destructive to magnetic fluctuations with any wavenumber in the case of intermediate valence.