Journal ArticleDOI
Superconductivity in the Bi - Sr/K - Ca/Na - Cu - O system
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TLDR
In this article, the role of double doping at the Ca and Sr sites simultaneously in the Bi-2212 composition was studied and it was found that the structure is single-phase Bi-2012.Abstract:
Samples with the stoichiometric composition with x = 0.1 and y = 0.1, 0.2, 0.3 and 0.4 were prepared by the solid state reaction method. The role of Na and K doped at the Ca and Sr sites simultaneously in the Bi-2212 composition was studied. From the x-ray diffraction data it was found that the structure is single-phase Bi-2212. From the resistivity data the varies from 63 to 67 K for different dopant levels. The diamagnetic nature of the samples was confirmed by ac susceptibility measurements. The oxygen content was determined by the two-step iodometric titration technique. The present results on the effect of double doping are compared with those of single dopants published earlier by our group. The microstructures of the samples were examined by scanning electron microscopy.read more
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Journal ArticleDOI
Broader perspective on the high-temperature superconduct- ing YBa2Cu3Oy system: The real role of the oxygen content.
TL;DR: These data are interpreted to demonstrate that the (Cu-O) charge in the sheets largely determines T/sub c/ and that the varying oxygen content and the chains merely provide an insulating reservoir of charge.
Journal ArticleDOI
Correlation of Tc with hole concentration in La2-xSrx
TL;DR: In this paper, the electron deficiency (hole concentration) in a superconducting system was determined by a chemical method and the results showed a direct correlation between the hole concentration and the Sr concentration.
Journal ArticleDOI
Chain-fragment doping and the phase-diagram of yba2cu3o7-x
TL;DR: Un modele de structure de defaut du compose non stœchiometrique, combine a l'approximation des liaisons fortes, rend compte des transitions supraconductrice and magnetique du materiau, mettant ainsi en evidence l'importance des trous dans l'sapparition des phases suprachonductrice et antiferromagnetique.
Journal ArticleDOI
The influence of oxygen on the physical properties of the superconducting series Bi2.1(CaχSr1−χ)n+1Cun+4+δ
R. G. Buckley,J. L. Tallon,I. W. M. Brown,M.R. Presland,N.E. Flower,P.W. Gilberd,Mark E. Bowden,N.B. Milestone +7 more
TL;DR: The sensitivity of Tc to oxygen sorption and the Ca to Sr ratio has been studied for the homologous series Bi2 in this article, where single phase n=2 samples were equilibrated under a fixed partial pressure of oxygen at temperatures between 300 and 850°C and quenched in liquid nitrogen.
Journal ArticleDOI
Correlation between Tc and hole concentration in the cation-substituted Bi2Sr2CaCu2O8+δ system
TL;DR: In this article, the correlation between superconducting T c and hole concentration was investigated in the Bi 2 Sr 2 CaCu 2 O 8+δ system and it was shown that T c increases, takes a maximum at the hole concentration corresponding to 0.2-0.3 holes per CuO 2 unit, and then decreases, with increasing hole concentration.