Continuous YBa 2Cu 3O 7-tape deposition by thermal evaporation

Abstract

Ni and Ni-alloy rolling assisted biaxially textured substrates provided both from IFW Dresden and an industrial partner (Plansee GmbH) were employed for the deposition of YBCO-coated conductors by thermal evaporation. The main advantages of this process are high volume deposition rates and relatively low substrate temperatures of 680 °C. As a consequence, a simple, economic, and very thin 100 nm CeO 2 buffer layer has turned out to be sufficient for high quality YBCO growth. For samples up to 20 cm long, critical current densities of 1.2 MA/cm 2 were achieved at 77 K and 2 μm thick films sustained transport currents beyond 150 A. Recently, the first continuously operating prototype tape deposition system based on thermal evaporation has been put into operation. A reel-to-reel tape winding mechanism is capable of handling YBCO and buffer layer deposition on tape 10 mm wide and up to 100 m long has been implemented. The YBCO-deposition speed of 4 m/h for a 1 μm layer.