Time-resolved magneto-optical experiments in Cd1-xMnxTe/ZnTe multiple quantum wells

Optical pump-probe experiments were performed in Cd0.9Mn0.1Te/ZnTe multiple quantum wells to study the dynamics of the exciton magnetic polaron in this material. Two transient absorptions of opposite sign were observed. The first signal is negative and indicates the decrease of optical absorption, as the excitons are approaching saturation. The second signal is positive and is interpreted as the absorption of "new excitons'' after the initial excitons created by the pump pulse have decayed leaving behind a magnetic polarized Mn environment. The spin relaxation time of the Mn ions has been determined to be 601 ps. Finally, we discuss the effect of the polaron-polaron interaction, relevant in our experiment because we saturate the excitons in the quantum wells. (C) 1999 American Institute of Physics. [S0021-8979(99)43108-1].