SHOCK-LOADING EFFECTS ON SUPERCONDUCTIVITY OF HGBA2CUOY

We have investigated shock-lending effects on the structural and super conducting properties of a high-T-c superconducting oxide HgBa2CuOy (H g-1201) by X-ray powder diffraction analysis, magnetic measurements an d electron microscopy. Most of the shock experiment were performed usi ng sample with pre-cooling to liquid nitrogen temperature in order to prevent decomposition due to temperature rise. The width of magnetizat ion hysteresis (Delta M) of Hg-1201 was reduced by shock-loading, but it recovered and improved by subsequent appropriate annealing. The mag netization hysteresis loops and TEM observation indicate: that this im provement of Delta M is probably caused by defects as pinning centers which were introduced by shock-loading and preserved by the annealing. The present study demonstrates that the pre-cooled shock-loading meth od is effective for introducing pinning centers into high-T-c supercon ductors, even for the composition including a volatile element such as Hg. (C) 1997 Elsevier Science B.V.