A Novel All-Conductive Architecture on Biaxially Textured Metal Substrates for YBCO Coated Conductors

In order to avoid thermal destruction of the superconductor in case of overcurrent, and improve the engineering current density J _E of the tapes, a novel buffer architecture, i.e., conductive SrRuO₃/TiN, has been developed on biaxially textured Ni-5 at.%W substrate for YBa₂Cu₃O_7?x (YBCO) coated conductors using pulsed laser deposition. The conductive TiN served as the effective seed and barrier layer because of low diffusion of metal atoms in the TiN layer, and the epitaxial conductive SrRuO₃ with good lattice match with the YBCO material, and was used as the cap layer. The X-ray diffraction showed the TiN and SrRuO₃ films had a perfect c-axis orientation and very good out-of-plane and in-plane texture. Atomic force microscopy indicated a very flat and dense TiN film with a layer-by-layer growth mode, and the root mean square surface roughness (R _rms) of the SrRuO₃ was less than 5 nm over a 2 μm × 2 μm scan area. The current–voltage curves of SRO/TiN/NiW showed a good conductivity of 16.7 Ω at the applied voltage of zero.