Probing hole-induced ferromagnetic exchange in magnetic semiconductors by inelastic neutron scattering

The effect of hole doping on the exchange coupling of the nearest neighbor (NN) Mn pairs in Zn${}_{1-x}$Mn${}_x$Te is probed by inelastic neutron scattering. The difference in the NN exchange energy $\mathrm{\Delta }{J}_1$ in the presence and in the absence of the holes is determined. The obtained value of $\mathrm{\Delta }{J}_1$ is in good agreement with the predictions of the Zener/RKKY model, even on the insulator side of the metal-insulator transition.