EFFECTIVE EXCHANGE INTERACTION FOR RARE-EARTHS IN METALS

A simple model for the calculation of the effective exchange coupling between f magnetic moments and d-character conduction electrons is proposed. Two situations are considered, namely stable dilute magnetic rare earth impurities in transition hosts and rare earth intermetallic compounds. The authors' model, as applied to the dilute case, may qualitatively account for the observed trends of the measured g shifts as a function of the position in the periodic table of the transition metal host. Numerical calculations are performed for some simple band models to illustrate the predictions of the model. g shift data for concentrated gadolinium intermetallics are discussed in a qualitative way.