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 ${\mathrm{cm}}^{-1\mathrm{}}$. Polarized spectra of 10-30-μm single crystals of this phase are consistent with the tetragonal average structure determined by single-crystal x-ray diffraction measurements on the same samples.