Interlayer Coupling in EuS-Based Superlattices (Dependence on the Energy Structure of Non-Magnetic Layer)

The interlayer coupling between ferromagnetic EuS layers separated by spacer layers of diamagnetic insulators, YbSe and SrS, is studied within a 3D tight-binding model. The dependencies of the coupling strength on the energy structure of the spacer, on strains resulting from the lattice mismatch between the superlattice constituents, as well as on an applied hydrostatic pressure and lattice deformations, are presented. The sign and the range of the obtained coupling agree with the behavior of magnetic correlations observed recently in neutron reflectivity spectra of EuS/YbSe superlattices.