Ab initio local-spin-density study of oscillatory exchange coupling in Fe/Au multilayers

Fully self-consistent ab initio local-spin-density calculations of the interlayer exchange coupling (IEC) in Fe/Au multilayers have been performed. The thickness of the ferromagnetic body-centred cubic Fe layers has been kept fixed at five monolayers (ML), the thickness of the face-centred cubic Au spacer layers has been varied between 2 and 30 ML. Agreement of the calculated and observed oscillation periods of the interlayer exchange coupling has been obtained. To verify the Rudermann-Kittel-Kasuya-Yoshida and quantum-well (QW) pictures for the IEC, detailed investigations of the Fermi surface of Au and of the modulation of the Bloch states in the spacer layer by means of QW oscillations have been performed.