Superconductivity suppression of R(Ba1−zRz)2Cu3O7+δ (R=Nd, Pr) probed by soft-x-ray absorption spectroscopy

J. M. Chen; R. S. Liu; P. Nachimuthu; M. J. Kramer; K. W. Dennis; R. W. McCallum

doi:10.1103/PhysRevB.59.3855

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Superconductivity suppression of R(Ba1−zRz)2Cu3O7+δ (R=Nd, Pr) probed by soft-x-ray absorption spectroscopy

J. M. Chen, R. S. Liu, P. Nachimuthu, M. J. Kramer, K. W. Dennis, R. W. McCallum

DOI 10.1103/PhysRevB.59.3855 · Physical Review B

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Abstract

O K-edge x-ray-absorption near-edge-structure (XANES) spectra of (Nd1−xPrx)1.05Ba1.95Cu3O7 for x=0–0.5 and Nd1.05(Ba1−zPrz)1.95Cu3O7+δ for z=0–0.25 were performed to search for microstructural features and hole distribution related to the superconducting properties. Near the O 1s edge, prepeaks at ∼527.6 and ∼528.3 eV are assigned to transitions into O 2p holes located in the CuO3 ribbons and CuO2 planes, respectively. As deduced from O 1s absorption spectra of (Nd1−xPrx)1.05Ba1.95Cu3O7 for x=0–0.5, the hole concentrations in the CuO2 planes and CuO3 ribbons decrease monotonically with increasing Pr doping. The present XANES results clearly reveal that the suppression of superconductivity with Pr doping in (Nd1−xPrx)1.05Ba1.95Cu3O7 results predominantly from the hole depletion effect. The effect of Pr on the Ba site in Nd1.05(Ba1−zPrz)1.95Cu3O7+δ is to reduce the hole concentration in the CuO2 planes and to create localized fivefold Cu chain sites. Tc of Nd1.05(Ba1−zPrz)1.95Cu3O7+δ is depressed upon Pr doping, primarily due to hole filling and hole localization. Compared to (Nd1−xPrx)1.05Ba1.95Cu3O7, the enhanced suppression of Tc in Nd1.05(Ba1−zPrz)1.95Cu3O7+δ is primarily due to the hole localization.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
(Nd1-xPrx)1.05Ba1.95Cu3O7 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	92	Pressure not reported	unknown
(Nd1-xPrx)1.05Ba1.95Cu3O7 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	20	Pressure not reported	unknown
Nd1.05(Ba1-zPrz)1.95Cu3O7 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	92	Pressure not reported	unknown
YBa2Cu3O7 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	92	Pressure not reported	unknown