Effects of 173mev xe ion irradiation on epitaxial yba2cu30 films

Epitaxially grown YBau302 films have been irradiated with 173 MeV^l29 Xe ions. A nonlinear decrease of the critical superconducting transition temperature T, and an exponential increase of the resistivity p is observed. "he c-axis parameter is extended to about 12w with increasing Xe fluence and the twin boundaries disappear. The 1-2-3 phase is amorphized along the paths of the Xe ions within an area of 40 A in diameter. A defect-induced enhancement of the critical current density j, in magnetic fields B is observed after low fluencies only if the flux lines are aligned parallel to the amorphized ion traces.