Rietveld analysis of the modulated structure in the superconducting oxide Bi sub 2 (Sr,Ca) sub 3 Cu sub 2 O sub 8+ x

Journal Article · Sat Sep 01 00:00:00 EDT 1990 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.42.4228· OSTI ID:6484396

Yamamoto, A; Onoda, M; Takayama-Muromachi, E; Izumi, F ^[1]; Ishigaki, T; Asano, H ^[2]

---

1. National Institute for Research in Inorganic Materials, Tsukuba 305 (Japan)
2. Institute of Materials Science, University of Tsukuba, Tsukuba 305 (Japan)

The modulated structure of the high-{ital T}{sub {ital c}} superconductor Bi{sub 2}(Sr,Ca){sub 3}Cu{sub 2}O{sub 8+{ital x}} was analyzed with a newly developed Rietveld refinement program for modulated structures. The structure refinement was made by the simultaneous refinement method using x-ray and time-of-flight neutron-diffraction data. It has a one-dimensionally modulated structure with {ital N} {ital Bbmb}/1{bar 1}1, {ital a}=5.3957(3), {ital b}=5.3971(3), {ital c}=30.649(1) A, and {bold k}=0.2118(1){bold b}{sup *}. Atoms in Bi-O, Sr-O, Cu-O, and Ca layers are all greatly displaced from their average positions. In particular Bi atoms are displaced mainly along the {ital b} axis, forming Bi-condensed and Bi-dilute regions. The characteristic feature of the structure is the existence of extra oxygens, giving {ital x}=1.0, in the Bi-dilute region of the Bi-O layer. Bi has a distorted rocksalt-type oxygen coordination with four short Bi-O bonds in the Bi-condensed region and a deformed square pyramidal coordination with five Bi-O bonds in the Bi-dilute region. The apical oxygen of a CuO{sub 5} pyramid, which joins Cu to Bi, moves along with Bi, distorting the pyramid considerably.

• OSTI ID: 6484396
• Journal Information: Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 42:7; ISSN 0163-1829; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
360204 -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALINE EARTH METAL COMPOUNDS
BISMUTH COMPOUNDS
BISMUTH OXIDES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
COHERENT SCATTERING
COPPER COMPOUNDS
COPPER OXIDES
DIFFRACTION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
MINERALS
NEUTRON DIFFRACTION
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PEROVSKITE
PEROVSKITES
PHYSICAL PROPERTIES
SCATTERING
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
STRUCTURAL CHEMICAL ANALYSIS
SUPERCONDUCTIVITY
TITANIUM COMPOUNDS
TITANIUM OXIDES
TRANSITION ELEMENT COMPOUNDS
X-RAY DIFFRACTION