Critical current enhancement in YBa/sub 2/Cu/sub 3/O/sub 7- delta / single crystal by 200 MeV proton irradiation

Radiation damage studies have been carried out using a beam of 200-MeV protons directed along the two major symmetry directions of YBa/sub 2/Cu/sub 3/O/sub 7- delta /. These beams create rather light damage tracks along their path, usually of single ion displacements. Strong pinning then depends on a line of pinning sites parallel to the vortex core. For radiation parallel to the ab-plane, relatively small doses greatly enhance the critical currents parallel to the c-axis and a strong anisotropy is observed depending on the direction of the vortices relative to the damage tracks. In the limit of high dose, 10/sup 16/ protons/cm/sup 2/, the damage is so uniform that the anisotropy effects are less pronounced.<>