Radial changes in the microstructure of LFZ-textured Bi-2212 thin rods induced by stoichiometry modifications

Three different Bi-2212 powders, with stoichiometric deviations both in the Bi and Sr content as well as in the Bi/Sr ratio, have been used as precursors in the processing of laser floating zone-textured thin rods. The developed microstructure in the as-grown and annealed rods has been studied by ICP analysis, scanning electron microscopy and energy dispersive spectroscopy microanalysis. The marked differences in phase distribution, composition and concentration found among the rods have been correlated with the initial stoichiometry. Finally, the effect of these microstructural inhomogeneities on the critical temperature, critical current density at 77 K and pinning behaviour of the rods is discussed