Raman study of pure and Ce doped single crystals of Nd 2− xCexCuO 4− y

Abstract

We present the polarized Raman spectra from single crystals of Nd 2CuO 4− y obtained at room temperature and by micro-Raman technique. Three of the four Raman active phonons predicted by factor-group analysis are found at 229 (A 1g ), 330 (B 1g ), 488 (E g) cm − 1 and attributed to the certain lattice vibrations. The Raman forbidden band around 580 cm − 1 probably induced by oxygen vacancies is also observed. The oxygen E g mode at 488 cm − 1 and the band at 580 cm − 1 are seen to be sensitive to oxygen deficiency. In contrast to the Sr doped La 2 CuO 4 , the doping with Ce supresses the intensity of the A 1g (Nd) peak at 229 cm − 1 .