Electron and hole spin dynamics in magnetic semiconductors

We studied the electron and hole spin dynamics in magnetic semiconductor quantum wells on pico- and femtosecond time scales by means of time-resolved magnetization modulation spectroscopy. Spin relaxation times of ∼10 ps (electrons) and ∼100 to 200 fs (holes) are found at room temperature for 15/15 monolayer CdTe/Cd0.88Mn0.12Te structures. Monitoring the decay of an optically induced spin density as a function of the Mn concentration, we conclude that the loss of the electron spin is related to spin-flip scattering via exchange with the large magnetic moments at the Mn sites