  In intrinsic magnetic semiconductors, the absorption of a single photon can
generate a spin polaron, whose magnetic moment reaches many thousands of Bohr
magnetons [1.2]. Here we investigate photoinduced spin polarons, using Monte
Carlo simulations. In antiferromagnetic semiconductors, photoinduced spin
polarons are most efficiently generated in the whole temperature interval up to
the phase transition, whereas in ferromagnetic semiconductors much larger spin
polarons can be photoinduced, but only around the phase transition temperature.
Because Monte Carlo simulations are computationally expensive, we developed an
analytical model, based on the Weiss field theory. Although the Weiss model
does not provide as much information as a Monte Carlo simulation, such as spin
texture and fluctuations, it yields formulas that can be used to estimate
instantly the expected photoinduced spin polaron size in many intrinsic
magnetic semiconductors.
