Chemical solution deposition of lanthanum zirconate barrier layers applied to low-cost coated-conductor fabrication

Epitaxial lanthanum zirconate (LZO) buffer layers have been grown by sol-gel processing on Ni–W substrates. We report on the application of these oxide films as seed and barrier layers in coated conductor fabrication as potentially simpler, lower cost coated-conductor architecture. The LZO films, about 80–100-nm thick, were found to have dense, crack-free surfaces with high surface crystallinity. Using 0.2-μm YBCO deposited by pulsed laser deposition, a critical current density of 2 MA/cm² has been demonstrated on the LZO films (YBCO/LZO/Ni–W). Using 0.8-μm YBCO deposited using metal organic decomposition, a critical current density of 1.7 MA/cm² and a critical current of 135 A/cm have been demonstrated on the LZO barrier layer with a sputtered CeO₂ cap layer (YBCO/CeO₂/LZO/Ni–W). These results offer promise to replace several of the vacuum-deposited layers in the typical coated conductor architecture (YBCO/CeO₂/YSZ/Y₂O₃/Ni/Ni-W).