WIDE-RANGE MU-RAMAN MEASUREMENTS OF YBA2CU3O7-Y SINGLE-CRYSTALS

Single Crystals of YBa2Cu3O7-y have been measured by Raman spectroscop y in the spectral range of possible electronic background. Mu-Raman te chnique has been applied in order to investigate small (1 mum2) defini te parts of the sample. The polarization selection rules have been mea sured including the the zz and zx polarizations. Contributions of the spectrometer characteristics (insufficient laser beam supression, lumi niscence and Raman response of the entrance slit, etc.) to the long ra nge background have been quantitatively determined. The absolute spect ral density of the scattering cross section has been estimated in comp arison with the phonon intensity and was found to be 1.1 10(-7) sr-1 for the xx polarization of the Raman-background.