Raman study of the effect of oxygen stoichiometry on the phonon spectrum of the high-Tc superconductor YBa2Cu3Ox

We have carried out a study of the effect of oxygen stoichiometry on the k=0 phonon spectrum of the high-Tc superconductor YBa2Cu3Ox using Raman spectroscopy. Polycrystalline samples were prepared with oxygen content x varying from 7.0, where the material is orthorhombic and superconducting, to 6.0, where it is tetragonal and semiconducting. The frequency and intensity of the k=0 phonon modes of Ag symmetry at 151, 340, 435, and 502 cm-1 (for x=7) were studied as a function of oxygen content. © 1988 The American Physical Society.