Magnetooptical investigations of PbEuTe

MBE grown PbEuTe samples with Eu-contents between 0 and 1.4% were investigated using a variety of experimental methods as interband magnetoabsorption, photomodulated reflectivity and CARS (coherent anti-Stokes Raman scattering) to obtain reliable bandparameters for this system. Compared to other semimagnetic IV-VI compounds like PbMnTe or PbEuSe the spectra exhibited significant differences. The photomodulated reflectivity even without magnetic field showed signatures besides the one originating from the fundamental gap. We attribute those to impurity related transitions. The magnetotransmission minima of samples with higher Eu-contents were rather broad superpositions of unresolved transitions particularly in Voigt configuration. The exchange interaction between free carriers and localised magnetic moments of the Eu-ions is by far weaker than in Mn-based semimagnetic IV-VI compounds but the same order of magnitude as in PbEuSe. The data were interpreted in the framework of the Mitchell & Wallis bandstructure model with the exchange interaction taken into account in mean field approximation.