Control of the growth mechanism of (119) Bi-2223 superconducting thin films. Two-dimensional nucleation growth and step-flow growth

Films of (119) Bi-2223 high-T-c superconductor, potentially useful for future sandwich-stacked structures exhibiting Josephson effect have been prepared by MOCVD on (100) NdGaO3 and (110) SrTiO3 flat and vicinal substrates with different off-angles. It is shown that off-angle is a key parameter in growth control mechanism of the films. In-plane aligned films, with regular morphology and low roughness as well as having maximum zero-resistivity critical temperature: of T-c0=67.2K and T-c0=74K when "single" and "two"-temperature growth routes are used, respectively, have been obtained for high of-angles (20 degrees). Growth mechanism is changing from a two-dimensional type for the flat substrate to a step-flow one for vicinal substrates.