Berlin 2005 – scientific programme
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TT: Tiefe Temperaturen
TT 23: Posters Superconductivity, Solids at Low Temperature
TT 23.11: Poster
Monday, March 7, 2005, 14:00–18:00, Poster TU D
Optimization of thick YBa2Cu3O7−x coated conductors produced by the TFA process — •Thomas Thersleff, Martina Falter, Heike Schlörb, Ludwig Schultz, and Bernhard Holzapfel — IFW Dresden, Helmholzstr. 20, 01069 Dresden
In this study, the effect of layer thickness, furnace ramp rate, and peak reaction temperature on YBCO layers chemically deposited onto single-crystal STO using the TFA process is assessed. First, layer thickness was increased by coating substrates multiple times. After each coating, the substrates were pyrolized up to 400∘C in a humid flowing gas O2 furnace. A single coating with our standard TFA precursor produces a layer ∼ 200 nm thick. Second, single layers were subjected to a slow heating ramp rate of 150 K/h in the 400-750∘C region. Third, other single layer samples were reacted at a depressed peak temperature of 760∘C to avoid reaction at the film boundary. Results show that substrates coated up to three times retain superconductivity with a Δ Tc of 3.9 K. XRD indicates the presence of BaF2, suggesting further temperature refinement is necessary. The slower ramp rate for single layers results in superior current transport properties, with Jc as high as 5 MA/cm2. Samples reacted at 760∘C maintain superconductivity with a Δ Tc as low as 1.4 K.