Antiferromagnetic interlayer coupling in EuS/YbSe superlattices

Semi-insulating EuS/YbSe superlattices were fabricated and studied both experimentally and theoretically. Antiferromagnetic correlations between ferromagnetic EuS layers were observed in neutron reflectivity spectra for samples with thin spacer layers (up to 20 A). This is explained by a model in which the interlayer exchange coupling is dependent upon the electronic band structure of the superlattice. The calculated strength and the range of the coupling are in qualitative agreement with the experimental findings.