Single-crystal micro-Raman spectroscopy of phases in the Y-Ba-Cu-O superconductor.

Single-crystal micro-Raman spectroscopy is used to characterize the structures and phonon properties of the YBa/sub 2/Cu/sub 3/O/sub 6+//sub x/ and Y/sub 2/BaCuO/sub 5/ phases present in the original 93-K Y-Ba-Cu-O superconducting compound. The vibrational Raman spectrum of the opaque YBa/sub 2/Cu/sub 3/O/sub 6+//sub x/ phase consists of prominent bands at 142, 338, 483, and 595 cm/sup -1/. Polarized spectra of 10--30-..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.