EFFECTIVE-MASS APPROACH TO THE RKKY INTERACTION IN MAGNETIC MULTILAYERS

We present a theoretical study of the RKKY coupling in magnetic multilayers based on an effective-mass model with a single quantum well or a superlattice potential. It is found that the oscillation period is determined by the nesting vector of the Fermi surface of the spacer regardless of the depth of the quantum well, while the coupling strength and the phase of oscillation are affected by the presence of the quantum well. The magnetic-layer thickness dependence of the RKKY coupling for the superlattice is investigated. It is found that the RKKY coupling integrated over the magnetic layer is a strong oscillatory function of the magnetic-layer thickness with a period related to the nesting vector of the Fermi surface for the magnetic material. The coupling across a quantum barrier is also studied. © 1995 The American Physical Society.