Correlation of radial inhomogeneties and critical current at 77 K in LFZ Bi-2212 textured thin rods

The fabrication of thin Bi-2212 rods by laser floating zone techniques gives high critical currents, I c, but strong radial inhomogeneities in microstructure and physical properties. By changing the precursor stoichiometry or the processing parameters, we have succeeded in improving the homogeneity and the I c values. Towards the centre of the rods, the superconducting material tends to have lower T c values associated to higher Bi content in the Bi-2212 superconducting grains. At 77 K, this gradient of Bi originates strong variations of critical current density across the rod.