Role of isovalent substitution of strontium for barium in the superconducting properties of cuprates with thallium monolayers

Journal Article · Thu Apr 01 04:00:00 EST 1993 · Chemistry of Materials; (United States)

DOI:https://doi.org/10.1021/cm00028a027· OSTI ID:6266531

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

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1. Universite de CEAN, Caen (France)

The isovalent substitution of strontium for barium in thallium monolayer cuprates is studied; three series of oxides have been isolated and characterized by X-ray diffraction: the 1201 phases TlBa[sub 1.2][sub [minus]][sub x]Sr[sub x]La[sub 0.8]CuO[sub 5][sub [minus]][delta] with O [le] x [le] 1.20, the 1212 phase TlBaSrCaCu[sub 2]O[sub 7][sub [minus]][delta], and the 1223 phases TlBa[sub 2][sub [minus]][sub x]Sr[sub x]Ca[sub 2]Cu[sub 3]O[sub 9][sub [minus]][delta] (0.50 [le]x[le] 1.50). The superconducting properties of thesee cuprates are optimized by Ar-H[sub 2] annealing at low temperature. It is demonstrated that, contrary to thallium bilayer cuprates, the critical temperature of thes phases is not significantly affected by the Sr substitution. The 1201 cuprates are all superconducting with very similar T[sub c]'s, close to 40 K, whatever x, i.e., equally for pure barium as for pure strontium phase. Similarly the 1212 phase TlBaSrCaCu[sub 2]O[sub 7][sub [minus]][delta], with a T[sub c] of 100 K, can be considered more interesting than TlBa[sub 1.5]Sr[sub 0.5]Ca[sub 2]Cu[sub 3]O[sub 9][sub [minus]][delta] exhibits the highest T[sub c], 124 K, which has been registered up to now in the 1223 series, showing that the multiplicity of the thallium layers does not play a predominant role for superconductivity. Attention is drawn to the crucial role of the experimental conditions of annealing for the optimization of the hole carrier density. 20 refs., 12 figs., 2 tabs.

• OSTI ID: 6266531
• Journal Information: Chemistry of Materials; (United States), Journal Name: Chemistry of Materials; (United States) Vol. 5:4; ISSN CMATEX; ISSN 0897-4756
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360207* -- Ceramics
Cermets
& Refractories-- Superconducting Properties-- (1992-)
ALKALINE EARTH METAL COMPOUNDS
ANNEALING
BARIUM COMPOUNDS
BARIUM OXIDES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CARRIER DENSITY
CHALCOGENIDES
CHEMICAL COMPOSITION
COHERENT SCATTERING
COPPER COMPOUNDS
CRITICAL TEMPERATURE
CUPRATES
DIFFRACTION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
HEAT TREATMENTS
HIGH-TC SUPERCONDUCTORS
LANTHANUM COMPOUNDS
LANTHANUM OXIDES
LAYERS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
SCATTERING
STOICHIOMETRY
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
SUPERCONDUCTIVITY
SUPERCONDUCTORS
THALLIUM COMPOUNDS
THALLIUM OXIDES
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
X-RAY DIFFRACTION