Structural and Electrical Properties of Biaxially Textured YBa_2Cu_3O_(7-x), Thin Films on Buffered Ni-based Alloy Substrates

摘要

Oxide high-T_c superconducting wires and tapes with high critical current density (J_c) are essential to future electrical power applications. Recently, YBa_2Cu3O_(7-x) (YBCO) thin films grown on Ni-based alloy tapes have attracted intense interest because of their promise for these applications. To achieve high J_c, buffer layers are necessary for fabricating biaxially aligned YBCO thin films. In our studies, yttria-stabilized zirconia (YSZ) layers were deposited on Ni-based alloy substrates by ion-beam assisted deposition, and CeO_2 buffer layers were subsequently deposited on the YSZ layer by pulsed laser deposition (PLD) or electron beam evaporation. In addition, MgO layers were deposited on Ni-based alloy substrates by inclined substrate deposition. Finally, biaxially textured YBCO thin films were deposited on these buffered metallic substrates by PLD under optimized conditions. The orientation and in-plane textures of YBCO and the buffer layers were characterized by X-ray diffraction θ/2θ-scans, φ-scans, and pole figure analysis. The superconductive transition features were examined by measuring inductive T_c and transport J_c.