MultipleMn2+-Spin-Flip Raman Scattering at High Fields via Magnetic Polaron States in Semimagnetic Quantum Wells

We observed up to 15 paramagnetic resonance Raman lines due to collective multiple spin flips within the Zeeman split ${\mathrm{Mn}}^{2+}$ ground state ${}^6{S}_{5/2}$ in a quantum well structure with semimagnetic ${\mathrm{Cd}}_{0.98}{\mathrm{Mn}}_{0.02}\mathrm{Te}$ wells and nonmagnetic ${\mathrm{Cd}}_{0.76}{\mathrm{Mn}}_{0.24}\mathrm{Te}$ barriers with external magnetic fields $B_{\mathrm{ext}}\le 7.5$ T. This effect appears near resonance with the heavy-hole transitions of narrow quantum wells in the Voigt backscattering geometry and can be explained by a precession of the total spin of all ${\mathrm{Mn}}^{2+}$ ions in the sum of external and exchange field ( ${\overrightarrow{B}}_{\mathrm{ext}}\perp {\overrightarrow{B}}_{\mathrm{exch}}$), the latter produced by the heavy hole.