Relaxation dynamics of ferromagnetic domains in (Cd,Mn)Te quantum wells

We present a magneto-optical study of the magnetization dynamics in ferromagnetic quantum wells in the time range down to 20 ns. We use a small electromagnet coil to produce short pulses of magnetic field. The magnetization relaxation after the pulse (observed through PL polarization) is faster than 20 ns in the paramagnetic state. Decreasing the temperature below the Curie temperature TC results in an increase of the relaxation time up to View the MathML source. This relaxation corresponds to the dynamics of the ferromagnetic domains. The mobility of the domains increases with temperature.