Kerr effect investigations of magnetic interlayer interactions in EuS-PbS multilayers

Kerr magnetometry was employed to study the temperature dependence of magne tization and magnetic hysteresis loops in ferromagnetic EuS-PbS semiconduct or multilayers in the temperature range T = 3-35 K at low magnetic fields H less than or equal to 150 Oe. For EuS-PbS/KCl(100) structures with ultrath in non-magnetic PbS spacer of I nm, we observed a maximum on the temperatur e dependence of magnetization at low fields H less than or equal to 30 Oe. For higher fields, we found for these structures a regular mean-field-like increase in magnetization with decreasing temperature. The same regular beh avior was also found for EuS-PbS/KCl structures with thicker PbS spacer, as well as for all EuS-PbS/BaF2(111) multilayers independently of spacer thic kness. For qualitative interpretation of these findings, we consider two ma gnetic contributions to the total energy of EuS-PbS multilayers: the Zeeman energy and the antiferromagnetic interlayer exchange coupling between ferr omagnetic EuS layers via diamagnetic PbS spacer.