The size and strain effects on the Raman spectra of Ce1−xNdxO2−δ (0≤x≤0.25) nanopowders

Ultrafine Ce1−xNdxO2−δ (x=0–0.25) powders were synthesized by self-propagating room temperature synthesis. Raman spectra were measured at room temperature in the 300–700 cm−1 spectral range. The shift and asymmetric broadening of the Raman F2g mode at about 454 cm−1 in pure and doped ceria samples could be explained with combined size and inhomogenous strain effects. Increased concentration of O2− vacancies with doping is followed by an appearance of new Raman feature at about 545 cm−1.