Enhancement of in-field critical current density by irradiation of MeV-energy ions in YBCO films prepared by fluorine-free metal-organic deposition

We performed irradiation of epitaxial YBa2Cu3O7 films grown on CeO2-buffered SrTiO3 substrates by fluorine-free metal organic deposition with 3-MeV Fe2+ ions to study their effects on critical current density (Jc). We observed an increase of in-field Jc by up to 70%, which did not show a significant field-angle dependence. Since the ion energy used in this study is two orders of magnitude lower than those in majority of the previous works with a similar concept, our results indicate that the enhancement of Jc by ion irradiation in high-temperature superconducting films has wider processing window than previously recognized.