Improved YBCO coated conductors using alternate buffer architectures

The Rolling-Assisted Biaxially Textured Substrates (RABiTS) process has been identified as one of the leading candidates for the fabrication of high performance YBa₂Cu₃O_7-δ (YBCO) coated conductors. The RABiTS process uses standard thermomechanical processing to obtain long lengths of flexible, biaxially oriented substrates with smooth surfaces. The strong biaxial texture of the metal is then transferred to the superconductor by the deposition of intermediate oxide buffers that serve both as a chemical and structural buffer. The typical three-layer RABiTS architecture consists of an e-beam Y₂O₃ seed, sputtered YSZ barrier and a sputtered CeO₂ cap layer. Chemical solution deposition of buffer layers offers potential cost advantage relative to physical vapor deposition (PVD) processes. Our main goal of this study is to develop simplified buffer architectures and demonstrate high J_c Metal-Organic Deposition (MOD)-YBCO films on all-MOD buffers. La₂Zr₂O₇ (LZO)/CeO₂ buffers have been identified as potential candidates for this study. MOD-YBCO films with a critical current, I_c of 212 A/cm have been achieved on MOD-LZO seeds with sputtered YSZ and CeO₂ cap layers. In addition, MOD-YBCO films with a critical current, I_c of 140 A/cm have been achieved on all MOD buffers of LZO/CeO₂ for the first time. This offers a potential toward fabrication of lower cost YBCO coated conductors.