Inelastic light scattering in α-Fe2O3: Phonon vs magnon scattering

Raman scattering measurements of α-Fe2O3 at temperatures between 300 and 1175 K and of Fe2−xCrxO3 mixed oxides at 300 K have been performed. The temperature dependence of the frequency, width, and intensity of the 1320 cm−1 peak near and above the Néel temperature (960 K) of α-Fe2O3 establishes that this peak arises from phonon scattering and not from two-magnon scattering as previously reported in the literature. The 1320 cm-1 peak is shown to be an overtone of a phonon which is forbidden and unobserved in α-Fe2O3 but is observed in Fe2O3-Cr2O3 solid solutions.