Large $Jc$ enhancement by ion irradiation for thick $YBa2Cu3O7−δ$ films prepared by photoassisted metalorganic chemical vapor deposition

Thick superconducting films of $YBa2Cu3O7−δ$ grown by photoassisted metalorganic chemical vapor deposition that have shown a decrease of $Jc$ with increasing thickness (>1 μm) have been exposed to ion irradiation in an attempt to enhance $Jc.$ A 4.5 μm thick film irradiated with 1 MeV protons at a dose of $3×1014/cm2$ has shown an increase of $Jc$ by a factor of nearly $20–1.7×106 A/cm2$ corroborating the proposal that a lack of pinning centers in the grown thick films, due to their high crystalline quality, contributed to the observed decrease of $Jc$ with increasing film thickness.