Epitaxy of buffer layer and superconducting performance development of YBCO on bi-layer buffers coated on Ni5W by all CSD

Textured La2Zr2O7 (LZO) films have been fabricated onto textured metallic Ni-5 at.%W (Ni5W) tapes using a reel-to-reel chemical solution deposition (CSD) system. Subsequently, CeO2 cap and YBCO superconducting layers have successfully deposited on the LZO buffered substrates in sequence by CSD method, indicating good structural transition and smooth surface morphology of such the buffer layer. We have evaluated the effect of the travel speed of the tape during the annealing process of the LZO layer on the texture and superconducting performance of the final YBCO layers deposited on Ni5W/LZO/CeO2 substrates by all chemical method. The appearance of outgrown grains and pinholes on the surface of CeO2 layer results in the formation a-axis grains and impurity, which leads to the decrease of superconducting performance of YBCO layer. The high c-axis-oriented YBCO film grown on the LZO/CeO2 buffered Ni5W metallic tape exhibits a high critical current density Jc of 2.1 MA/cm2 at 77 K and 0 T when the preferred travel speed of tape of 4.2 m/h is adopted to fabricate the underlying LZO film.