Single-Crystal Micro-Raman Spectroscopy of Phases in the Y-Ba-Cu-O Superconductor

Abstract

Single-crystal micro-Raman spectroscopy is used to characterize the structures and phonon properties of the $\mathrm{Y}{\mathrm{Ba}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{6+x}$ and ${\mathrm{Y}}_{2}$BaCu${\mathrm{O}}_{5}$ phases present in the original 93-K Y-Ba-Cu-O superconducting compound. The vibrational Raman spectrum of the opaque $\mathrm{Y}{\mathrm{Ba}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{6+x}$ phase consists of prominent bands at 142, 338, 483, and 595 ${\mathrm{cm}}^{\ensuremath{-}1}$. Polarized spectra of 10-30-\ensuremath{\mu}m single crystals of this phase are consistent with the tetragonal average structure determined by single-crystal x-ray diffraction measurements on the same samples.