Phonon Characterization of Raman Spectra in High T_cSuperconductors Y_1-xGd_xBa₂Cu₃O_7-δ

Concentration-dependent Raman spectra of Y_1-xGd_xBa₂Cu₃O_7-δ(x=0.4, 0.6, 0.8 and 1.0) show that the Raman mode from O(4) bridging shifts upward due to the increased symmetry of crystal potential. The linewidth and intensity of 508cm^-1 mode are decreased and increased with increasing x, respectively which is attributed to the charge transfer from the CuO basal planes to the CuO₂ planes. Two second-order Raman modes at 798 and 896cm^-1 have been observed and confirmed.