Raman study of lattice modes in the high–critical-temperature superconductor Y-Ba-Cu-O

Raman spectra of high-temperature superconducting materials composed of Y-Ba-Cu-O compounds are reported for the first time. These spectra show numerous lattice modes which are attributed both to the superconducting phase ${\mathrm{YBa}}_2$ ${\mathrm{Cu}}_3$ ${\mathrm{O}}_{\mathrm{x}}$ and also to the impurity phases of ${\mathrm{BaCuO}}_2$ and ${\mathrm{Y}}_2$ ${\mathrm{BaCuO}}_5$. Raman spectroscopy is shown to be a sensitive probe of both the phonon structure of the superconductor and of the impurity phases in the material.