Regensburg 2007 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 8: Superconductivity - Poster Session

TT 8.1: Poster

Montag, 26. März 2007, 14:00–17:45, Poster A

Analysis and Optimization of Oxide Buffer Layers Related to YBCO Films Deposited by CSD and MOCVD on Biaxially Textured NiW Substrates — •Elmiloudi Elmechaouri, Burckhard Mönter, and Martin Hoffmann — Bergische Universität Wuppertal Gaußstraße 20, 42119 Wuppertal

The studies based on epitaxial buffer layers of CeO₂ and Yttria-stabilised ZrO₂ (YSZ) having been deposited on biaxially textured nickel substrates using thermal reactive evaporation and rf sputtering in continuous deposition processes in reel-to-reel systems. Starting from the well known architecture of CeO₂/ YSZ/ CeO₂ the thickness of the different buffer layers was varied. Misorientation, porosity and roughness was analyzed and optimized for YBCO deposition by MOCVD und CSD. The grain morphology and the behavior of the grain boundary networks in YBCO coated conductors have been shown to depend on both the YBCO deposition method and the buffers layer. The possibility of using only one and two buffers layer and conductive layers of perovskite type was studied. X-ray-diffraction, SEM and TEM have been used to investigate the microstructure of both the buffer layers and the YBCO films. Optimal growth conditions of YBCO for the different buffer layers have been determined. YBCO films were deposited by CSD, MOCVD and for comparison by high pressure dc sputtering, resulting on CeO₂/YSZ/CeO₂ buffered substrates Jc values higher than 2 MA/cm². The resulting superconducting properties were measured by inductive characterization and by Hall probe measurements of the Magnetic field due to induced magnetization currents.