Thickness dependence of superconducting critical current density in vicinal YBa2Cu3O7-δ thick films

In YBa2Cu3O7-delta (YBCO) thick films, the superconducting critical current density (J(c)) decreases with increasing film thickness (t). The mechanisms responsible for this J(c)-t behavior remain unclear. To probe the correlation between the film microstructure and J(c)-thickness behavior, we have deposited YBCO thick films up to 3.0 mum in thickness on flat and surface-miscut (100) SrTiO3 substrates with 5degrees, 10degrees, and 15degrees vicinal angles. The microstructures of the YBCO films were found to evolve differently on flat and miscut substrates, resulting in different J(c)-t behaviors. Surprisingly the small miscut angles of 5degrees-10degrees were favorable to obtain higher J(c) and smaller J(c) reduction at larger film thickness. (C) 2004 American Institute of Physics.