  We investigated the dynamics of the interaction between spin-polarized
photo-created carriers and Mn ions on InGaAs/GaAs:Mn structures. The carriers
are confined in an InGaAs quantum well and the Mn ions come from a Mn
delta-layer grown at the GaAs barrier close to the well. Even though the
carriers and the Mn ions are spatially separated, the interaction between them
is demonstrated by time-resolved spin-polarized photoluminescence measurements.
Using a pre-pulse laser excitation with an opposite circular-polarization
clearly reduces the polarization degree of the quantum-well emission for
samples where a strong magnetic interaction is observed. The results
demonstrate that the Mn ions act as a spin-memory that can be optically
controlled by the polarization of the photocreated carriers. On the other hand,
the spin-polarized Mn ions also affect the spin-polarization of the
subsequently created carriers as observed by their spin relaxation time. These
effects fade away with increasing time delays between the pulses as well as
with increasing temperatures.
