We address our full attention to the various useful capabilities of the Raman scattering technique for characterizing high-Tc superconducting oxides. The powerful aspect of Raman spectroscopy is demonstrated with regard to detection of traces of impurities as compared with the conventional X-ray diffraction technique. Oxygen disordering within CuO chains in Co-doped Y123 type materials is sensitively detected by the Raman scattering technique, the degree of which is proportional to the intensity of the disorder induced Raman mode above 550 cm-1. The phonon Raman spectra of (Pb2Cu)Sr2Y1-xCaxCu2O8+d, (Pb2Cu)Sr0.9La1.1CuO6+d and (Pb0.5Cu0.5)Sr2YCu2O7+d are investigated and phonon assignments compatible with the layer stacking sequences found in these Pb-based cuprates are proposed. Raman scattering can also be used as a means to detect insulator-to-metal transitions in various high-Tc cuprates, an example of which is demonstrated for (Pb2Cu)Sr2Y1-xCaxCu2O8+d; the intensity for the B1g OCu mode abruptly drops across the insulator-to-metal transition as a result of the increased metallic screening in the hole-introduced samples.
ASJC Scopus subject areas
- Condensed Matter Physics