Properties of YBa2Cu3O7 thin films deposited on substrates and bicrystals with vicinal offcut and realization of high IcRn Junctions

Poppe, T. D.; Shadrin, P.; Urban, K.; Faley, M. M.; Divin, Y. Y.; Jia, C. L.; Wu, J. S.

doi:10.1109/77.919884

Journal Article

Properties of YBa2Cu3O7 thin films deposited on substrates and bicrystals with vicinal offcut and realization of high IcRn Junctions

Poppe, T. D.FZJ* ; Divin, Y. Y.FZJ* ; Faley, M. M.FZJ* ; Wu, J. S.FZJ* ; Jia, C. L.FZJ* ; Shadrin, P.FZJ* ; Urban, K.FZJ*

2001
IEEE New York, NY

IEEE transactions on applied superconductivity 11, 3768 - 3771 (2001) [10.1109/77.919884]

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Please use a persistent id in citations: http://hdl.handle.net/2128/1073 doi:10.1109/77.919884

Abstract: The surface morphology, microstructure and transport properties of epitaxial YBa2Cu3O7 and PrBa2Cu3O7 thin films and heterostructures deposited on slightly vicinal substrates of SrTiO3 by high pressure oxygen sputtering were studied. The vicinal angles of the substrates and bicrystals were less then 13 degrees. Depending on the tilt angle of the substrate a transition from spiral or island to step-flow growth leading to an improvement of the surface roughness was observed. Atomic force and transmission electron microscopy were used for these investigations. Furthermore, electrical and structural properties of YBa2Cu3O7 thin films on vicinal offcut SrTiO3 bicrystals with different grain boundary types were studied. This included junctions with a 2x 12 degrees tilt or twist of the YBa2Cu3O7 c-axis across the grain boundary. In comparison to conventional [001]-tilt grain boundaries bicrystal Josephson junctions [100]-tilt grain boundaries showed high I-c R-n -products of up to 1.2 meV at 77 K and up to 8 meV at 4.2 K. IV-curve instabilities, probably of magnetic origin due to flux flow in the electrodes, often could he observed for junctions biased with high current densities.

Keyword(s): J ; high-temperature superconductors (auto) ; Josephson junctions (auto) ; bicrystals (auto) ; grain boundaries (auto) ; vicinal substrates (auto)