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 thi s material. Two transient absorptions of opposite sign were observed. The f irst signal is negative and indicates the decrease of optical absorption, a s the excitons are approaching saturation. The second signal is positive an d is interpreted as the absorption of "new excitons'' after the initial exc itons created by the pump pulse have decayed leaving behind a magnetic pola rized Mn environment. The spin relaxation time of the Mn ions has been dete rmined 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].