Microstructural development and superconducting properties of BaO/sub 2/-added Bi/sub 2/Sr/sub 2/CaCu/sub 2/O/sub 8+x/

Investigations on the effects of Ba additions in Bi-2212 superconductors are focussed on compositional, microstructural, and magnetization studies. In previous studies, we showed that BaO/sub 2/ reacts with Bi-2212 to form second phases. Zero-field and in-field transport properties in Ag-clad BaO/sub 2/ added Bi-2212 tapes had been improved at 4.2 K. SEM micrographs, pole figures, and transport critical currents versus magnetic field orientation suggest that BaO/sub 2/ has a strong influence on the microstructural properties. Magnetization studies revealed that BaO/sub 2/ does not affect the pinning properties of optimally added Bi-2212. To estimate the potential of BaO/sub 2/ additions in creating possible pinning sites, TEM investigations were carried out focussing on sub-micrometer inclusions and growth defects in the superconducting phase.