Exchange coupling in magnetic superlattices

Abstract

Artificial magnetic superlattices composed of successive ferromagnetic and paramagnetic layers have received much attention in recent years due to their scientific and technological relevance. While the strength of the exchange coupling and the oscillation period depend on the details of the Fermi surfaces involved, the overall features appear universal. More complex couplings are observed for magnetic superlattices with chromium spacer layer. This is due to the intrinsic spin density wave of Cr. Extensive synchrotron and neutron scattering experiments have now unraveled the Neel- state of thin Cr layers and proximity effects between Fe and Cr, elucidating the mutual interdependence of Cr spin structure and Fe exchange coupling. In Co/Cr superlattices the structural mismatch between hcp Co and bcc Cr adds another complexity, which affects strongly the magnetic anisotropy. Both, the current status and understanding of the exchange coupling in Fe/Cr(001) and Co/Cr(001) superlattices is briefly reviewed here.