Biaxially Textured Buffer Layers on Large-Area Polycrystalline Substrates

Abstract

AbstractBiaxially textured yttria stabilized zirconia (YSZ) buffer layers were deposited on long polycrystalline metallic tapes by an ion-beam-assisted deposition process (IBAD) to serve as templates for high-current carrying Y1Ba2Cu3O7-x (YBCO) films. YSZ was deposited by a dualionbeam equipment with two 11 cm Kaufman ion sources. The coating of large-area technical substrates, large in comparison with the ion sources, requires substrate movements to render YSZ films of homogeneous texture quality. These movements can hinder cooling of the metallic tapes in the absence of a thermal contact. Therefore, the temperature of those small-heat-capacity substrates could rise to above 100 °C within minutes, causing a decrease of the in-plane alignment of YSZ. The investigation of the temperature dependence of the IBAD process reveals that the best results of the in-plane alignment could be obtained by room temperature deposition. Applying high tape velocities hinder a rise of the deposition temperature to above 90 °C. Therefore, it is possible to deposit YSZ films on metal tapes (up to 60 mm × 1000 mm) with in-plane textures down to 15° full width at half maximum (FWHM), which allow their coating with highcurrent-carrying YBCO films.