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

Journal Article · Thu Apr 01 00:00:00 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), Vol. 5:4; ISSN 0897-4756
• Country of Publication: United States
• Language: English

Related Subjects

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