Interaction of magnetic impurities in Cu and Ag

Abstract

Ab initio calculations for the electronic structure of pairs of magnetic impurities like Cr, Mn and Fe in Cu and Ag are presented. The calculations are based on density functional theory and apply the KKR Green function method. The authors calculate the local densities of states and the local moments for both the ferromagnetic and antiferromagnetic pair configurations. In particular, they estimate the energy difference between these configurations for different interatomic impurity distances. They show that this RKKY-type energy can be obtained in first order from the difference between the single-particle energies of these configurations calculated with the same 'frozen' impurity potential. In both hosts, two Fe impurities couple strongly ferromagnetically on nearest-neighbour sites, whereas Cr impurities show a strong antiferromagnetic interaction. Mn impurities are an intermediate case, interacting weakly antiferromagnetically.