MAGNETIC-INTERACTIONS IN THE METALLIC PHASE OF THE COPPER OXIDES - A FERMI-LIQUID DESCRIPTION

The magnetic interactions in the metallic phase of the copper oxides and associated dynamical susceptibility are calculated within a Fermi liquid scheme in which the Cu electrons are nearly localized and the oxygen bandwidth assumes physical values. Both superexchange (J(s)) and RKKY interactions (J(R)) emerge from our diagrammatic formalism on a similar footing. With increasing carrier concentration, J(s) decreases rapidly, while J(R) abruptly increases from zero. These self consistently determined interactions and "renormalized" bandstructure lead to an enhanced stability of the Fermi liquid phase.