Effect of Ga and Zn doping on coherent transition of YBCO superconductor

Abstract

The simultaneous incorporation of Ga³⁺and Zn²⁺to the Cu-site of YBa₂Cu₃O₇_-δ has been analyzed for microstructural and electrical properties. Temperature-dependent electrical resistivity, X-ray diffraction and SEM analysis of a set of YBa₂(Cu_0.95Zn_0.05_-xGa_x)₃O₇_-y films prepared by solid state reaction technique have been investigated to study the substitutional effects of Ga and Zn at chain and plane site of Cu, respectively. The redistribution of charges in the superconducting system due to oxygen content and the resistance of the weak-links related inhomogeneities give rise to <i>T</i>_{c<i> </i>}degradation and dual values of exponents in the <i>T</i>_c0 region. The exponent values for fluctuation conductivity in the <i>T</i>_c0 region decrease with increase of substitution concentration. The dual exponent character shows that the intergranular weak links develop more resistance with increasing impurities.