Local structure around F in the fluorine-doped Nd sub 2 CuO sub 4 superconductor

Journal Article · Wed Jul 01 04:00:00 EDT 1992 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.46.443· OSTI ID:5002304

Krol, A; Soo, Y L; Ming, Z H; Huang, S; Kao, Y H ^[1]; Smith, G C ^[2]; Lee, K ^[3]; James, A C.W.P.; Murphy, D W ^[4]

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1. Department of Physics and New York State Institute on Superconductivity, State University of New York at Buffalo, Buffalo, New York 14260 (United States)
2. Brookhaven National Laboratory, Upton, New York 11973 (United States)
3. Department of Chemistry, State University of New York at Stony Brook, Stony Brook, New York 11794 (United States)
4. AT T Bell Laboratories, Murray Hill, New Jersey 07974 (United States)

Soft-x-ray-absorption fine-structure (XAFS) measurements were performed at the F {ital K} edge on Nd{sub 2}CuO{sub 4{minus}{ital x}}F{sub {ital x}} compounds with {ital x}=0.15 and 0.30. It is found that a majority of F atoms substitute for the O(2) sites in fluorite-type NdO layers between CuO{sub 2} sheets. For the compositions {ital x}=0.15 and 0.30, a fraction of 0.33{plus minus}0.15 and 0.39{plus minus}0.14 of F dopants, respectively, substitute for the O(1) site in the CuO{sub 2} planes. Fluorine anions placed at the O(2) sites in the NdO layers form a reservoir of extra electrons for the superconducting CuO{sub 2} sheets in Nd{sub 2}CuO{sub 4{minus}{ital x}}F{sub {ital x}} superconductors, analogous to the substitution of Ce or Th cations for Nd. This observation thus provides evidence for a symmetry of anionic (F) and cationic (Ce and Th) substitution in the NdO layers in connection with superconductivity.

• DOE Contract Number: FG02-87ER45283; AC02-76CH00016
• OSTI ID: 5002304
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 46:1; ISSN PRBMD; ISSN 0163-1829
• Country of Publication: United States
• Language: English

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