Structure and superconductivity without apical oxygens in (Ca,Na)[sub 2]CuO[sub 2]Cl[sub 2]

Journal Article · Sat Apr 01 04:00:00 EST 1995 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.51.8434· OSTI ID:6583738

Argyriou, D N; Jorgensen, J D; Hitterman, R L ^[1]; Hiroi, Z; Kobayashi, N; Takano, M ^[2]

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1. Science and Technology Center for Superconductivity and Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)
2. Institute for Chemical Research, Kyoto University, Uji Kyoto-fu 611 (Japan)

Recently superconductivity has been reported in (Ca,Na)[sub 2]CuO[sub 2]Cl[sub 2] in which the apical anion position was proposed to be occupied by Cl [Hiroi [ital et] [ital al]., Nature 371, 139 (1994)]. In this paper we report a neutron powder diffraction investigation of nonsuperconducting Ca[sub 2]CuO[sub 2]Cl[sub 2] and superconducting (Ca,Na)[sub 2]CuO[sub 2]Cl[sub 2] ([ital T][sub [ital c]]=26 K). We confirm that in both compounds the apical anion position is fully occupied by Cl. Unlike the recently reported superconductor Sr[sub 2]CuO[sub 2]F[sub 2+[delta]], in (Ca,Na)[sub 2]CuO[sub 2]Cl[sub 2] we find little evidence for the presence of interstitial atoms. In our structural data the substitution of Na[sup +] for Ca[sup 2+] is evidenced by a shortening of the Cu-O bond and lengthening of the Cu-Cl bond. The bond valence of the Cu atom increases, consistent with holes being created by the Na substitution.

• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 6583738
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 51:13; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

665411* -- Basic Superconductivity Studies-- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
BOND LENGTHS
CALCIUM CHLORIDES
CALCIUM COMPOUNDS
CALCIUM HALIDES
CHALCOGENIDES
CHLORIDES
CHLORINE COMPOUNDS
COHERENT SCATTERING
COPPER CHLORIDES
COPPER COMPOUNDS
COPPER HALIDES
COPPER OXIDES
CRYSTAL STRUCTURE
DIFFRACTION
DIMENSIONS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
HALIDES
HALOGEN COMPOUNDS
LENGTH
NEUTRON DIFFRACTION
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SCATTERING
SODIUM CHLORIDES
SODIUM COMPOUNDS
SUPERCONDUCTIVITY
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE