ON THE EVOLUTION OF PHASES IN POLYCRYSTALLINE Li-DOPED 2212 BSCCO AND ENHANCED SUPERCONDUCTING BEHAVIOUR VIA n(Li,alpha)T REACTIONS

We report on the evolution of phases upon cooling of partially-melted Bi-Sr-Ca-Cu-Li-O powders and tapes and on enhanced magnetic flux-pinning through irradiation. Enhanced resistive transitions have been obtained despite significant amounts of (Sr1-delta,Ca-delta)(n)CuOx phases (where n=1 or 2). Here, the evolution of phases is investigated in Li-doped and undoped 2212 via extensive microstructural characterizations. To enhance the flux-pinning, we have neutron irradiated Li-doped and undoped 2212. In addition to the neutron collision-induced damage, the n+(6) Li -> T-3+(4)alpha+4.89 MeV and the n+Li-7 -> T-3 + (4)alpha + n - 2.5 MeV fission reactions produce a homogeneous distribution of high and low energy charged particles. Effects of irradiation upon the magnetically measured T-c and J(c,m)(H) are reported. Differences between the effects upon doped and undoped superconducting powders are discussed to highlight the effects of the charged particle damage.