Development of Solution Buffer Layers for RABiTS Based YBCO Coated Conductors

Abstract

Abstract—The main objective of this research is to find a suitable alternate solution based seed layer for the standard RABiTS three-layer architecture of physical vapor deposited CeO􀀀 cap/YSZ barrier/Y􀀀O seed on Ni-5%W metal tape. In the present work, we have identified CeO􀀀 buffer layer as a potential replacement for Y􀀀O seeds. Using a metal-organic deposition (MOD) process, we have grown smooth, crack-free, epitaxial thin films of CeO􀀀 (pure and Zr, Cu and Gd-doped) directly on biaxially textured Ni-5W substrates in short lengths. Detailed XRD studies indicate that a single epitaxial CeO􀀀 phase with slightly improved out-of-plane texture compared to the texture of the underlying Ni-W substrates can be achieved in pure, undoped CeO􀀀 samples. We have also demonstrated the growth of YSZ barrier layers on pure CeO􀀀 seeds using sputtering. Both sputtered CeO􀀀 cap layers and MOD-YBCO films were grown epitaxially on these YSZ-buffered MOD-CeO􀀀/Ni-5W substrates. High critical currents per unit width, of 264 A/cm (critical current density, of 3.3 MA/cm􀀀) at 77 K and 0.01 T was achieved for 0.8 m thick MOD-YBCO films grown on MOD-CeO􀀀 seeds. These results indicate that CeO􀀀 films can be grown directly on Ni-5W substrates and still support high performance YBCO coated conductors. This work holds promise for a route for producing low-cost buffer architecture for RABiTS based YBCO coated conductors.