RADIATION-DAMAGE AND FLUX-PINNING IN HIGH-TEMPERATURE SUPERCONDUCTORS

Radiation damage and flux pinning of high temperature superconducting (HTS) materials were studied with MeV ion beams and internal MeV ion i rradiation by thermal neutron triggered reaction products. The materia ls used included epitaxial thin film of YBCO, melt-textured YBCO and s ingle crystal YBCO. The flux pinning was measured by a vibrating sampl e magnetometer (VSM). The pinning mechanism in each material was radia tion-induced weak pinning centers, resulting in an enhancement of crit ical current density (J(c)) by a factor of 6 and 18 in single crystal and melt-textured YBCO, respectively. Details of neutron-triggered int ernal irradiation and its possible application to bulk materials are d iscussed, The defect structure was observed with transmision electron microscopy (TEM) and compared with TRIM simulations.