Compositional dependence of the band structure and magnetic properties of PbSnMnTe narrow-gap semimagnetic semiconductor
Low-temperature measurements of the magnetic susceptibility, plasma reflectivity and Hall effect as a function of carrier-concentration were performed on Pb1-x-ySnxMnyTe samples with x=0.72 and y=0.03, 0.06, 0.08. The dependences of the paramagnetic Curie temperature and effective mass of holes on manganese content and carrier concentration were determined. The analysis of the experimental data has been performed assuming that two valence bands are relevant in the case of PbSnMnTe: the non-parabolic light-hole L band and the parabolic heavy-hole Sigma band. Theoretical calculations of the paramagnetic Curie temperature dependences on manganese content and carrier concentration were also performed on the basis of the band structure model mentioned above and assuming the RKKY exchange interaction between Mn spins. It was found that the compositional evolution of the band structure determined the carrier concentration dependence of the magnetic properties of PbSnMnTe.