Magnetic rare-earth superlattices (invited)

The magnetic structures of several single-crystal, magnetic rare-earth superlattice systems grown by molecular-beam epitaxy are reviewed. In particular, the results of recent neutron diffraction investigations of long-range magnetic order in Gd-Y, Dy-Y, Gd-Dy, and Ho-Y periodic superlattices are presented. In the Gd-Y system, an antiphase domain structure develops for certain Y layer spacings, whereas modified helical moment configurations are found to occur in the other systems, some of which are commensurate with the chemical superlattice wavelength. References are made to theoretical interaction mechanisms recently proposed to account for the magnetic states of these novel materials.