Application of textured IBAD-TiN buffer layers in coated conductor architectures

Abstract

Ion-beam assisted deposition (IBAD) is one of the major techniques for preparing highly textured templatesfor YBa2Cu3O7−x (YBCO) coated conductors. In most applications so far IBAD-MgO has beenused. TiN is an alternative material for the IBAD process showing a texturednucleation similar to MgO. Different amorphous or nanocrystalline seed layers such asAl2O3,Y2O3 orTa0.75Ni0.25 were found to be suitable for achieving strong cube textures in film thicknessesbelow 10 nm using reactive ion-beam assisted pulsed laser deposition. The biaxialtexture was preserved to a higher thickness using homoepitaxial growth athigher temperatures. Different buffer layer architectures based on IBAD-TiNhave been developed on Hastelloy substrates. An electrically conducting bufferlayer stack was realized using a double layer of Au and Ir with a final Nb-dopedSrTiO3 cap layer, enabling the epitaxial growth of YBCO on top.Alternatively, a robust simplified buffer architecture was studied usingSrZrO3 directly on TiN, leading to highly textured YBCO layers.