Two series of Y1-xCaxBa2Cu3Oy, x = 0.05 and 0.10, have been studied by O-1s X-ray absorption near-edge spectroscopy using synchrotron radiation. The characteristics of the decrease of Tc with the decrease of the oxygen content, y, are found different for the series of x = 0.05 and x = 0.10. The former reveals the importance of the holes on the apical oxygen sites. Through a cross examination between these two series of samples, direct evidences are observed that the reduction of the number of holes on the apical oxygen sites has a negative effect on the superconductivity in the underdoped region of Ca-doped YBCO system.
- High-T superconductor
- X-ray absorption spectrum
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering