X-ray absorption fine structure on the Cu K and the Pb L3-edges of PbBaSrY1-xCaxCu3O7+δ and Pb2Sr2Y1-xCaxCu3O8+δ systems has been measured. In the oxygen-deficient phase with δ=0 of these systems, the Cu K-near-edge spectra evidence the existence of Cu1+ comprised in OCuO linear chains. The Cu K-edge position shifts to higher energy retaining the Cu1+ feature by substitution of Y3+ with Ca2+ in the oxygen-deficient phase, indicating that holes are supplied to the CuO2 basal planes of the pyramids. The Pb valence is found to be mixed states of 2+ and 4+ in the oxygen-rich phases with δ>1. The average Pb valence is estimated as 3.3+ and 3.04+ in PbBaSrYCu3O8.4 and Pb2Sr2YCu3O9.5, respectively.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering