Raman spectra of (Pb2Cu)Sr2Y1-xCaxCu2O8+δ (Pb3212), (Pb2Cu)Sr0.9La1.1CuO6+δ (Pb3201), and (Pb0.5Cu0.5)Sr2YCu2O7+δ (Pb1212) were studied and vibrational assignments in harmony with the layer stacking sequences found in these Pb-based high-Tc superconducting oxides were proposed. In particular, the assignment of the 480- and 580-cm-1. Raman bands to oxygen in the PbO and SrO layers, respectively, was unambiguously established. In the case of Pb3212 we found that the intensities of modes connected to the CuO2-plane variations decreased with increasing carrier concentration. This effect was attributed to the increased metallic screening in the CuO2 planes that can be expected in the hole-rich Ca-doped samples.
|Number of pages
|Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy
|Published - 1999 Sept