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Bulletin of Materials Science

, Volume 14, Issue 3, pp 747–752 | Cite as

Fluctuation-induced excess conductivity in the compounds CaREBaCu3O7−y (RE=La and Sm)

  • H Krishnan
  • R Srinivasan
  • V Sankaranarayanan
  • C K Subramaniam
  • G V Subba Rao
International Conference On Superconductivity—II

Abstract

The compounds CaREBaCu3O7−y (RE=La and Sm) are tetragonal at room temperature withT c between 60 and 70 K. The single-phase compounds were prepared by solid-state reaction. The resistivity was measured by a four-probe technique in a continuous flow cryostat with the temperature being controlled to an accuracy of 10 mK. The resistivity vs temperature showed a break in slope around 180 K in CaLaBaCu3O7−y and around 220 K in CaSmBaCu3O7−y . The results were analysed for fluctuation conductivity from 180 K downwards. A plot of dρ/dT vsT showed a sharp peak atT m =69·69 K for La compound and 66·00 K for the Sm compound. Detailed analysis of the resistivity in the regionT on to 180 K was carried out using the procedure due to Veira and Vidal. The results are discussed in this paper.

Keywords

HighTc superconductors CaREBaCu3O7−y fluctuation excess conductivity 

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Copyright information

© Indian Academy of Sciences 1991

Authors and Affiliations

  • H Krishnan
    • 1
  • R Srinivasan
    • 1
  • V Sankaranarayanan
    • 1
  • C K Subramaniam
    • 1
  • G V Subba Rao
    • 1
  1. 1.Materials Science Research Centre, Department of PhysicsIndian Institute of TechnologyMadrasIndia

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