Role of oxygen in superconductivity of Nd2−xCexCuO4−y studied by x-ray-absorption near-edge structure
Hiroyuki Oyanagi, Yuko Yokoyama, Hirotaka Yamaguchi, Yuji Kuwahara, Toshikazu Katayama, Yoshikazu Nishihara
DOI 10.1103/PhysRevB.42.10136 · Physical Review B
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Abstract
The effect of reduction on the electron states of Nd2−xCexCuO4−y (0.15<x<0.17) has been revealed by x-ray-absorption near-edge structure on the Cu K edge for a series of samples annealed at various oxygen partial pressures (pO2=1–10−3 atm). We find that the Ce doping-induced states in the near-edge structure systematically increase the magnitude with the decrease of oxygen partial pressure, well correlating with the oxygen pressure dependence of superconducting fraction and Tc value. The results indicate that the reduction strongly enhances the electron density at the copper sites, through the removal of a small number of defect oxygen atoms that suppress n-type doping in the CuO2 plane.
Source-reported materials — not catalogue approval
| Formula | Reported Tc (K) | Pressure (GPa) | Type |
|---|---|---|---|
| Nd2-xCexCuO4-y Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | — | Pressure not reported | unknown |
| Nd1.85Ce0.15CuO4-y Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | — | Pressure not reported | unknown |
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