Nature of copper in the new cuprate superconductors Pb2Sr2Ca1−xLxCu3O8+δ

C. N. R. Rao; V. Bhat; R. Nagarajan; G. Ranga Rao; G. Sankar

doi:10.1103/PhysRevB.39.9621

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Nature of copper in the new cuprate superconductors Pb2Sr2Ca1−xLxCu3O8+δ

C. N. R. Rao, V. Bhat, R. Nagarajan, G. Ranga Rao, G. Sankar

DOI 10.1103/PhysRevB.39.9621 · Physical Review B

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Abstract

Based on Cu K-edge absorption spectroscopy as well as Cu(2p3/2) and Cu(LVV) Auger spectroscopies it is shown that the recently discovered Pb2Sr2Ca1−xLxCu3O8+δ (L=Y or Lu) superconductors contain well-defined Cu1+ species in admixture with Cu2+. The proportion of Cu1+ is small in the nonsuperconducting samples with x=1, a feature which is uniquely different from that in YBa2Cu3O7−δ.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
Pb2Sr2Ca0.5Y0.5Cu3O8+δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	65	Pressure not reported	onset
Pb2Sr2Ca0.25Y0.75Cu3O8+δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	75	Pressure not reported	onset
Pb2Sr2Ca0.5Lu0.5Cu3O8+δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	65	Pressure not reported	onset
Pb2Sr2Ca0.25Lu0.75Cu3O8+δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	73	Pressure not reported	onset