Indirect Exchange Interaction in Metals—A Status Report

Abstract

A survey is given of the indirect coupling of nuclear magnetic moments in metals via the hyperfine interaction with conduction electrons. The treatment is given in terms of the wavevector-dependent static susceptibility of the conduction electrons. The criterion for the absence of a long-range uniform magnetization is discussed. The usual divergence in the self-energy of a single nuclear magnetic moment in a metal is shown to be caused by the attribution of a zero range to the contact interaction, whereas the appropriate range is ħ/mc. The divergence recently claimed in the interaction between two nuclear moments at absolute zero is believed to be a manifestation of the Kondo effect. Mean free path and correlation effects are considered.