Formation of bound magnetic polarons in Cd1−x MnxTe crystals. Contribution of the average exchange field and thermodynamic fluctuations of the magnetization to the binding energy

It is shown that the temperature dependence of the binding energy of exciton-impurity complexes in the semimagnetic semiconductors Cd_1−x Mn_xTe (x≈0.05) is described well in the donor-electron model with an effective characteristic magnetic-polaron energy. The contributions of the average exchange field and of thermodynamic fluctuations of the magnetization to the binding energy and their variation with temperature with and without a weak magnetic field (H⩽3.5 kOe) are determined. How doping with scandium, vanadium, and cobalt effects the appearance of the magnetic-polaron in the experimental crystals was studied. Fiz. Tverd. Tela (St. Petersburg) 39, 527–535 (March 1997)