COLUMNAR DEFECTS IN YBA2CU3O7-DELTA INDUCED BY IRRADIATION WITH HIGH-ENERGY HEAVY-IONS

Defect microstructures in three YBa2Cu3O7-delta single crystals irradi ated with different high energy heavy ions show dramatically different damage morphologies. For Sn and Au projectiles with total energies of 580 MeV and 1.0 GeV, respectively, highly aligned tracks are observed which extend for many microns in the crystals. However, irradiation w ith 1.4 GeV Br ions results in the formation of spherical damage regio ns widely separated along the ion path through the entire crystal. The continuity of damage along the ion path for the different projectiles varies with the magnitude of the electronic energy loss.