Raman scattering by phonons and magnons in semimagnetic semiconductors: Cd1-xMnxTe

Cd1-xMnx Te alloys possess a homogeneous crystal phase having a zinc-blende structure for 0≤x≤0.7. Their Raman spectra exhibit two pairs of sharp lines characteristic of the zone center "CdTe-like" and "MnTe-like" LO-TO modes. Some quasicontinuous features in the Raman spectrum can be traced to first-order processes which become allowed as a result of the absence of strict translational symmetry and reflect the one-phonon density of states. In the antiferromagnetic phase of the alloys (x>0.6) and in the spin-glass phase (0.17≤x≤0.6), a new low-energy Raman line appears. We attribute it to an inelastic scattering involving the emission or absorption of a magnon. The polarization features and the temperature dependence of the magnon line are consistent with this assignment.