Strategic Buffer Layer Development for YBCO Coated Conductors

We have developed a simplified buffer layer architecture for the rolling-assisted biaxially textured substrates (RABiTS) template approach. The overall purpose of this research is to enable potentially a low-cost, high throughput and high yield manufacturing processes for buffer fabrication and to gain fundamental understanding of the growth of buffer layers for RABiTS templates. This understanding is critical to the development of a reliable, robust, and long-length manufacturing process for second generation wires. In this study, efforts are being made to either reduce the number of vacuum deposited layers or to replace one or more of these vacuum deposited layers with a solution based layer. We have chosen Gd₂O₃ - ZrO₂ system as a potential barrier layer for this study. We have deposited epitaxial Gadolinia Stabilized Zirconia (GSZ) (Zr_1-xGd_xOy; x = 0-1) films on 30-nm thick e-beam evaporated Y₂O₃ seeded Ni-W (3 at. %) (Ni-3W) substrates using a metal-organic decomposition (MOD) process. Detailed X-ray studies indicated that all of the MOD-GSZ layers were cube textured and both in-plane and out-of-plane lattice parameters increases linearly with increasing the Gd content. We have also developed process conditions for reactively sputter deposited epitaxial Gd₂Zr₂O₇ (Gadolinium Zirconium Oxide (GZO); Zr_1-xGd_xO_y (x = 0.5)) films on the e-beam evaporated Y₂O₃/Ni - 3W substrates. YBCO films with a critical current density J_c of 2.14 times 10⁶ A / cm² and 1.4 times 10⁶ A / cm² at 77 K and self-field were grown on the newly developed architectures of Gd₂Zr₂O₇/Y₂O₃/Ni - 3W and Zr_1-xGd_xO_y (x = 0.2)/Y₂O₃/Ni - 3W substrates, respectively using a puls- - ed laser deposition (PLD) process. This work promises a route for producing cost-effective simplified buffer architectures for the RABiTS-based YBCO coated conductors.