Enhanced Super conducting Properties and Defects in Shock Compacted YBa2Cu3O7.x and Shock-Synthesized TI2Ba2Cu06 Super conductors

Commercially obtained polycrystalline YBa2Cu307-x powders (~40 micron particle size) were shock consolidated using a cylindrical implosion geometry at peak pressures of ~1-5 GPa and powder packing density of -50%. The shock compacted powders were then subjected to controlled oxygen annealing treatments to homogenize the microstructural defects produced during shock compaction and optimize the particle size. The resulting shock processed and annealed samples showed significant improvement of flux pinning forces in contrast to conventionally sintered samples. The intergrain critical currents obtained via low-field and AC susceptibility data show an enhancement by a factor of three at temperatures between 4K and 78K, and magnetic fields up to 150 Oe. Even higher intergrain critical currents were obtained for samples that were shocked and then melt-processed. Electron microscopic analysis indicates formation of interpenetrating twins which may be the seat of defects in microcrystals. At the atomic scale level, the defects consist of intergrowths of a Y-Ba-Cu 223 phase sequence in bulk 123 structure. Some studies on shock-synthesized TI2Ba2Cu06 are also presented.
Part of ISBN 9781000943559, 9781003418146QC 20230831