Oscillatory coupling between interfaces in metallic multilayers

The authors have developed a theory that views the total energy of an array of multilayers as a weighted average of bulk contribution corrected by a sum of single-interface and interface-interface interactions terms. They demonstrate that they are due to the same quantum-mechanical property of a degenerate Fermi liquid in a localized external potential as that which gives rise to the Friedel charge and magnetic oscillation around an impurity and the corresponding Ruderman-Kittel-Kasuya-Yoshida (RKKY) interactions. They argue that the recently discovered oscillatory magnetic coupling between magnetic layers separated by paramagnetic metallic layers should be accompanied by elastic interactions that give rise to periodic strain modulations, Delta alpha / alpha , in the spacer layers.