Thallium nonstoichiometry in 2212-thallium cuprate

Journal Article · Fri Jan 31 23:00:00 EST 1992 · Journal of Solid State Chemistry; (United States)

DOI:https://doi.org/10.1016/S0022-4596(05)80260-9· OSTI ID:7201785

Michel, C; Martin, C; Hervieu, M; Maignan, A; Provost, J; Huve, M; Raveau, B ^[1]

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1. Lab. CRISMAT, Caen (France)

The study of thallium nonstoichiometry in the thallium 2212 cuprate by X-ray diffraction and electron microscopy has allowed a significant homogeneity range to be isolated, Tl{sub 2{minus}x}Ba{sub 2}CaCu{sub 2}O{sub 8{plus minus}{delta}} with 0{le}x{lt}0.4. The HREM study showed that thallium deficiency is not accommodated through an intergrowth mechanism but implies a statistical distribution of Tl atoms and vacancies in the thallium double layers. However, it appeared that modulated areas can arise from ions' and vacancies' local orderings in the (111) plane of the rock salt layers; they result in satellites in the E.D. patterns. The study of the superconducting properties of these oxides shows that the critical temperature is not greatly affected by the thallium nonstoichiometry, whereas hydrogen-argon annealings confirm the predominant role of oxygen non stoichiometry upon T{sub c}'s , allowing a (T{sub c}){sub R=0} of 120 K to be reached for x = 0.4. The deterioration of the grain boundaries by hydrogen annealing is also studied.

• OSTI ID: 7201785
• Journal Information: Journal of Solid State Chemistry; (United States), Journal Name: Journal of Solid State Chemistry; (United States) Vol. 96:2; ISSN 0022-4596; ISSN JSSCB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202 -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
360207* -- Ceramics
Cermets
& Refractories-- Superconducting Properties-- (1992-)
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
ALKALINE EARTH METAL COMPOUNDS
ANNEALING
BARIUM COMPOUNDS
BARIUM OXIDES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
CHARGED PARTICLES
COHERENT SCATTERING
COPPER COMPOUNDS
COPPER OXIDES
CRITICAL TEMPERATURE
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DATA
DIFFRACTION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRON MICROSCOPY
EXPERIMENTAL DATA
HEAT TREATMENTS
INFORMATION
IONS
MICROSCOPY
MILLER INDICES
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
POINT DEFECTS
RESOLUTION
SCATTERING
SPATIAL RESOLUTION
STOICHIOMETRY
SUPERCONDUCTORS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
THALLIUM COMPOUNDS
THALLIUM OXIDES
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
VACANCIES
X-RAY DIFFRACTION