Analysis of flux pinning in YBa2Cu3O7-δ films by nanoparticle-modified substrate surfaces

Enhanced in-field critical current density J(c) has been achieved in YBa2Cu3O7-delta (YBCO) films grown on single crystal and biaxially textured metal substrate surfaces that were pretreated with second-phase nanoscale MgO and BaZrO3 particles. Nanoparticles were applied using wet chemical solution-based approaches. Results obtained in this study are compared with our previous investigations on surface modified substrates with sputter processed Ir nanoparticles. Cross-sectional TEM analysis and details of the field-orientation dependence of J(c) are found to be similar for both sputtered and solution processed nanoparticle species. Present results show a more uniform dependence of J(c) over all orientations of magnetic field, along with improved irreversibility behavior. Irrespective of the decoration technique, scaling behavior of the normalized volume pinning force density, F-p, demonstrates the similarity of pinning mechanisms for these YBCO films deposited on artificially modified substrates.