TI/sub 2/BA/sub 2/CaCu/sub 2/O/sub 8/

Journal Article · Fri Jan 01 04:00:00 EST 1988 · Modern Physics Letters B; (USA)

DOI:https://doi.org/10.1142/S0217984988000345· OSTI ID:5612447

Maignan, A; Michel, C; Hervieu, M; Martin, C; Groult, D; Raveau, B ^[1]

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1. Laboratoire Crismat, Institut des Sciences de la Matiere et du Rayonnement, Campus 2, Bd du Marechal Juin, 14032 Caen Cedex (FR)

Tl/sub 2/Ba/sub 2/CaCu/sub 2/O/sub 8/ has been synthesized as a pure phase by reaction in sealed quartz tube. The structural model of this oxide has been established from X-ray diffractograms and high resolution electron microscopy. This tetragonal structure (a=3.860A, c=29.388A, space group I4/mmm) can be described as formed of (Ba/sub 2/Tl/sub 2/Cu/sub 2/O/sub 8/)/sub {infinity}/ layers interleaved with calcium ions. These layers are themselves described as the intergrowth of sodium chloride type (TIO)/sub {infinity}/ layers of corner-sharing pyramids (BaCuO/sub 3/)/sub {infinity}/ leading to the formulation ((BaCuO/sub 3/)/sub 2/(TIO)/sub 2/)/sub {infinity}/. Such a perfect structure Tl/sub 2/Ba/sub 2/CaCu/sub 2/O/sub 8/, which contains only Cu(II) cannot be at the origin of the superconductivity at 110{Kappa}. The superconducting properties may in fact be explained by the observation by HREM of extended defects of local composition TlBa/sub 2/CaCu/sub 2/O/sub 7/ for which a structural model is proposed. In a more general way the creation of thallium deficiency, according to the formulation Tl/sub 2-chi/Ba/sub 2/CaCu/sub 2/O/sub 8/ could be at the origin of superconductivity.

• OSTI ID: 5612447
• Journal Information: Modern Physics Letters B; (USA), Journal Name: Modern Physics Letters B; (USA) Vol. 2:5; ISSN MPLBE; ISSN 0217-9849
• 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
656002 -- Condensed Matter Physics-- General Techniques in Condensed Matter-- (1987-)
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
COHERENT SCATTERING
COPPER COMPOUNDS
COPPER OXIDES
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DIFFRACTION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRON MICROSCOPY
ELEMENTS
METALS
MICROSCOPY
MICROSTRUCTURE
OXIDES
OXYGEN COMPOUNDS
PHASE STUDIES
PHYSICAL PROPERTIES
POINT DEFECTS
SCATTERING
SUPERCONDUCTIVITY
SUPERCONDUCTORS
THALLIUM
THALLIUM COMPOUNDS
THALLIUM OXIDES
TRANSITION ELEMENT COMPOUNDS
VACANCIES
X-RAY DIFFRACTION