LARGE J(C) ENHANCEMENT BY ION IRRADIATION FOR THICK YBA2CU3O7-DELTA FILMS PREPARED BY PHOTOASSISTED METALORGANIC CHEMICAL-VAPOR-DEPOSITION

Thick superconducting films of YBa2Cu3O7-delta grown by photoassisted metalorganic chemical vapor deposition that have shown a decrease of J (c) with increasing thickness (>1 mu m) have been exposed to ion irrad iation in an attempt to enhance J(c). A 4.5 mu m thick film irradiated with 1 MeV protons at a dose of 3 x 10(14)/cm(2) has shown an increas e of J(c) by a factor of nearly 20 - 1.7 x 10(6) A/cm(2) corroborating the proposal that a lack of pinning centers in the grown thick films, due to their high crystalline quality, contributed to the observed de crease of J(c) with increasing film thickness. (C) 1997 American Insti tute of Physics.