PROCESSING EFFECTS ON MECHANICAL AND SUPERCONDUCTING PROPERTIES OF BI2201 AND BI2212 GLASS-CERAMICS

Bi2212 and Bi2201 were prepared by annealing of glass with the composi tion Bi2.18Sr2CaCu2O8+d. Using this preparation technique, structural and microstructural properties such as phase formation, grain size and oxygen content can easily be affected by different annealing conditio ns, i.e. by variation of time and temperature. Hence, the deformation behaviour and the critical temperature (T-c) are a function of the ann ealing conditions. This could be shown by creep experiments and AC sus ceptibility measurements. Samples with nanocrystalline microstructures exhibit substantially better plasticity under stress than samples wit h larger grains. Good superconducting properties could only be achieve d in nearly single-phase Bi2212 samples with grains extending over sev eral hundred nanometers to a few micrometers in the direction of the c axis.