The doping effect of Ca substitution in Y0.7 Ca0.3Ba2 Cu3Oy has been studied for y=6.9 and 6 by the x-ray absorption near edge spectroscopy (XANES). While Ca doping leads to an obvious increase in hole concentration in the CuO2 planes in Y0.7 Ca0.3 Ba2 Cu3 O6.9, XANES indicates absence of this doping effect in Y0.7 Ca0.3 Ba2 Cu3 O6. These two contradict results suggest that the doping effect by Ca substitution could be sensitive to the oxygen content when y ∼ 6.0. Comparisons with others' works are made.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Materials Science(all)
- Condensed Matter Physics