Figure 1.

(a) X-ray diffraction patterns of CeO_x, CeO_x:Gd5%, CeO_x:Gd9%, CeO_x:Gd14%, and CeO_x:Gd19%. The calculated grain sizes as determined by the Scherrer equation are given. (b) Raman spectra for CeO_2, Gd₂O_3, CeO_x, CeO_x:Gd5%, CeO_x:Gd9%, CeO_x:Gd14%, and CeO_x:Gd19%. The Raman spectra are normalized and vertically shifted using a small offset for each spectrum to facilitate line shape comparison. There is an increasing shift of the main Raman peak to lower wavenumbers related to the integration of Gd.