Influence of Local Potential on Exciton Splitting in Highly Diluted Cd1−x\text{}_{1-x}Mnx\text{}_{x}Te

We investigated magnetoreflectance and magnetization of highly diluted bulk Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te crystals 0.2% ≤ x ≤ 10%. The exchange constant in terms of mean field approximation and virtual crystal approximation (the ratio of the heavy hole exciton splitting to mean spin per unit cell) was evaluated and found x-dependent. This deviation from the mean field approximation and virtual crystal approximation prediction is caused by the local potential introduced by Mn ions. We discuss the problem within a Wigner-Seitz approach and within a model of magnetic and chemical disorder based on the alloy theory

Magnetic Properties of EuS/PbS Semiconducting Structures

We report results of magnetization study of EuS/PbS superstructures with different thicknesses of magnetic and nonmagnetic layers. Reduction of ferromagnetic phase transition temperature was found with decreasing EuS thickness. Reasonable description of this effect is obtained within the model based on the mean field approximation

A Photoluminescence Study in PbS-EuS Superlattices

Investigations of the photoluminescence of PbS-EuS superlattices deposited on (111)BaF$\text{}_{2}$ substrates are presented. Quantum-size and deformation effects in photoluminescence spectra are observed. The strain-induced gap shift and valence-band offset is determined from experimental results. A strong stimulated photoluminescence with relatively low threshold was observed. It was found that the photocarriers generated in EuS barrier strongly affect the population of PbS subbands

Magnetic Anisotropy in Eus-pbs Multilayers

We present the results of ferromagnetic resonance studies of the thickness dependence of magnetic anisotropy in 2 series of EuS-PbS multilayers grown on (111) BaF$\text{}_{2}$ and (100) KCl substrates with the EuS thickness varying in the range d=6-70 Å. The anisotropy constant K was found to follow the dependence K(d)=K$\text{}_{V}$+2K$\text{}_{S}$/d , with the surface term K$\text{}_{S}$ larger for layers grown on BaF$\text{}_{2}$ as compared to KCl. This difference is discussed in terms of different thermal stress-induced distortions of cubic crystal lattice of EuS. We found that the thickness of EuS layer required for the perpendicular (to the layer) magnetization is d ≤ 2-3 Å, i.e., it is below 1 monolayer