Raman Scattering Study of the Effect of Nd Substitution into Ba Sites on the Phonon Spectrum of Nd1+xBa2-xCu3Oy (x=0–0.4, y=∼7)

Abstract
We have carried out a study of the effect of trivalent Nd ion substitution into the divalent Ba site on the Raman spectra of Nd1+x Ba2-x Cu3O y (x=0–0.4, y=∼7) as a function of x. A systematic change occurs in the phonon band from 500 through 600 cm-1 which is related to the oxygen vibration in the BaO or CuO layer. The mode near 310 cm-1, which has been attributed to Cu(2)-O(2, 3) bending vibrations in the CuO2 layer, does not show substantial variation with an increase in x. These results are discussed in connection with the orbital character of the hole.