Nb Substituted Cu0.5Tl0.5Ba2(Ca3Nb1)Cu5O\(_{14-\delta}\) and Cu0.5Tl0.5Ba2(Ca4Nb1)Cu6O\(_{16-\delta}\) Superconductors

  • Nawazish A. Khan
  • Arshad Hussain


The effects of higher electro-negativity Nb substitution on the Ca site in Cu0.5Tl0.5Ba2 (Ca3Nb1)Cu5O\(_{14-\delta}\) and Cu0.5Tl0.5Ba2(Ca4Nb1)Cu6O\(_{16-\delta}\) superconductors have been investigated. The Nb doping has been found to increase the oxygen contents in Cu0.5Tl0.5Ba2O\(_{16-\delta}\) charge reservoir layer of the final compound. The post-annealing in the N2 atmosphere has been found to improve the superconducting properties; however, O2 annealing produced the material with inferior superconducting properties. The quantity of diamagnetism is increased with post-annealing in the nitrogen atmosphere; as N2 annealing helps in the formation of material with optimum carriers concentration in the CuO2 planes, which is done by the change in the charge state of thallium from Tl3+ to Tl1+. The Nb substitution has been found to develop the higher CuO2 planner phases such as Cu0.5Tl0.5Ba2Can −2Nb1Cun 2 n+4−δ (n=5,6) with enhanced T c's.


Nb-doped Cu0.5Tl0.5Ba2(Ca3Nb1)Cu5O\(_{14-\delta}\) and Cu0.5Tl0.5Ba2(Ca4Nb1)Cu6O\(_{16-\delta}\) superconductors normal pressure synthesis higher nCuO2 (n=5,6) planes 


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© Springer Science+Business Media, LLC 2007

Authors and Affiliations

  1. 1.Materials Science Laboratory, Department of PhysicsQuaid-i- Azam UniversityIslamabadPakistan

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