Heating of the spin system by nonequilibrium phonons in semimagnetic (Cd,Mn,Mg)Te quantum wells

We study the heating of the spin system of magnetic ions induced by ballistic acoustic nonequilibrium phonons in (Cd,Mn,Mg)Te-based semimagnetic quantum wells using exciton luminescence technique. We find that the temperature of the spin system in the presence of nonequilibrium phonons decreases with the increase of magnetic field. In the analysis, we use the well-known fact that phonon losses at the solid/liquid helium boundary increase with the increase of phonon energy. The results lead us to the conclusion that the spin-heating effect is induced by phonons with energies resonant to the Zeeman splitting of spin sublevels of Mn ions. We propose a type of the subterahertz phonon spectrometer that may be used for investigation of semiconductor nanostructures.