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Spray pyrolysis has been successfully used to synthesize many oxides, like transparent conducting films (SnO2, ZnO and InO3) or cuprate-based superconducting films. This technique has the great advantage of combining high deposition rates in a non-vacuum environment and cheap raw materials. In our work, spray pyrolysis has been used to grow superconducting epitaxial thick films of YBa2Cu3O7−δ on textured substrates. A precursor nitrate solution is atomized and carried towards a substrate, which is heated at 850 °C. After growth, oxygenation is carried out by cooling under oxygen flow. YBCO films deposited on a single-crystal (SrTiO3) exhibit a very good c-axis orientation (Δω = 0.4°) as well as an in-plane texture (Δφ = 0.6°). Transport measurement gives an Ic value close to 10 A (77 K, sf) on a 5-mm wide substrate. First YBCO depositions on metallic substrates display a reasonable out-of-plane texture (Δω = 7°) and a T c onset of 90 K. Furthermore, a prospective work on buffer layers (Y2O3, CeO2 and CuO) synthesis has been carried out. It has been evidenced a narrow relationship between the decomposition route of the precursors and the properties of the deposition. In certain cases NO2 outgassing can be problematic as it can induce cracks or foam morphology. |
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