Raman spectroscopy at room temperature was used to investigate defect structure and mixed valence states of Fe²⁺( Fe³⁺) doped CeO₂ nanopowders. Existence of CeO₂ fluorite cubic structure was characteristic for all investigated samples whereas the presence of first order Raman modes of Fe₂O₃ and Fe₃O₄ structural phases were not observed. Additional modes at 720 cm^-1, 1320 cm^-1 and 1600 cm^-1 are observed for doped samples and can be assigned to maghemite (g-Fe₂O₃) cation deficient structure, to 2LO IR-allowed overtone and two magnon features, respectively. This implies that our powders are composed of mixed valence states and have defective structure.

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