Shock-Wave Induced Changes in Superconductivity in YBa sub 2 Cu sub 3 O sub (7-delta)

Shock-wave loading produced significant changes in superconductivity in sintered YBa sub 2 Cu sub 3 O sub (7-delta) causing a broad transition with T sub c (R=0) ~40K. The normal-state resistivity increased by 20-50 times with the p-T curve exhibiting a semiconducting behavior. Comparative thermogravimetric analysis, however, indicated no loss of oxygen (delta~0.1) in the shock-loaded sample, and x-ray powder diffraction analysis showed no major changes except for slight line broadening. The observed semiconductive behavior and degradation in superconductivity is thus attributed to a rather subtle disturbance in crystal structure, the nature of which is not clearly understood at present.