EFFECT OF SILVER ADDITION TO THE BISMUTH LEAD STRONTIUM CALCIUM COPPER-OXYGEN SUPERCONDUCTOR - ENHANCEMENT IN CRITICAL-CURRENT DENSITY

Resistivity, XRD and a.c. susceptibility measurements have been carrie d out to study the effect of silver addition (0-50 wt%) to a Bi1.6Pb0. 4Sr2Ca2.2Cu3.5Oy composition prepared by two different techniques, nam ely, the usual solid state reaction technique and a solution technique . The specimens prepared by solid state technique show a degradation i n T(c) as well as J(c) (the critical current density computed from the qranular model of Clem) with the increase in silver concentration fro m 0 to 50 wt%. On the other hand, specimens prepared by the solution t echnique, which yields a material with strong intergrain links, show a systematic improvement in J(c) (except for 5wt% silver addition) righ t up to 50 wt%. The widely different results on silver addition to the Bi-system of the high-T(c) superconductors as reported by different a uthors can thus be attributed to the strength of the intergrain coupli ng which in turn will depend on preparation technique.