ENHANCED PARAMAGNETISM IN ULTRATHIN CD1-XMNXTE LAYERS

We have investigated Cd1-xMnxTe/Cd1-yMgyTe-quantum wells by low temper ature photoluminescence and photoluminescence excitation spectroscopy. The well widths vary between 2 and 100 monolayers and the manganese c ontents used are x = 0.07, 0.10 and 0.18. We have measured the Zeeman splitting of the heavy-hole exciton as a function of the well width an d the manganese content. The exciton is used as a sensitive local prob e to investigate the magnetism of Cd1-xMnxTe in quasi two-dimensional layers. In addition, we have calculated the Zeeman splitting variation ally. From the comparison of the experimental and numerical data we ob tain the effective spin component S-eff and the effective temperature T-eff. The deduced effective spin components increase with decreasing well width, whereas the effective temperatures decrease, demonstrating the reduction of antiferromagnetic ordering due to the reduction of d imensionality. Furthermore, we have calculated S-eff for thin Cd1-xMnx Te layers as a function of the manganese content and the layer thickne ss. The functional dependence of S-eff obtained theoretically is in go od agreement with the experimental data taking into account simultaneo usly both an interface disorder caused by segregation during growth an d the enhanced paramagnetism at the interface.