MAGNETOOPTICAL PROPERTIES OF SEMIMAGNETIC LEAD CHALCOGENIDES

Magneto-optical properties ot PbTe and PbSe alloyed with paramagnetic ions Mn and Eu are reviewed. The k . p theory of the band structure of IV-VI compounds is presented, taking into account the narrow energy gaps and strong spin-orbit interactions in the materials. The exchange interaction between the paramagnetic ions and mobile carriers is included in the framework of the mean-field approximation. The experimental data of various authors on magnetization, interband magneto-optics, intraband magneto-optics and four-wave mixing are presented. All results are successfully described by the theory, treating the exchange integrals as adjustable parameters. It is shown that the exchange interaction is of particular importance for the valence bands. Differences between semimagnetic behaviours of Mn-based and Eu-based systems are emphasized as well as those between the IV-VI and II-VI semimagnetic compounds.