Dynamics of photoinduced Faraday rotation in semimagnetic semiconductors

Abstract

Time-resolved Faraday rotation measurements on a nanosecond time scale are performed for Cd1−xMnxTe samples grown by two different techniques. The dependence of the observed photoinduced dynamics on the purity, Mn++ concentration (x=0.03, 0.10, 0.15, 0.3), excitation density, and temperature (100–290 K) reveals several novel features. The relaxation for pure samples is monoexponential at 100 K and is slowing down with increasing temperature, in strong contrast to impure samples, where the opposite behavior is observed. All experimental observations can be well explained in a simple model based on rate equations for the free-carrier populations, provided that recombination centers and impurity traps are included in the model.