Reel-to-reel MOCVD for YBCO coated conductor

A reel-to reel MOCVD system has been developed for a fast and economic process to get high quality YBCO coated conductor tapes. Several oxides buffer layer sequences (based on YSZ, CeO₂, Y₂O₃...) were then grown epitaxially on two kinds of tape. Effective stacking for MOCVD reported here are YSZ/Y₂O₃/YBCO and YSZ/CeO₂/YBCO, respectively, on oxidized Ni RABiTS microalloys (0,1% W) and on SS/YSZ (IBAD) tapes. First, EBSD and AFM techniques have been used to characterize the substrates. Superconducting YBCO films were fully characterized by SEM, XRD and AC susceptibility measurements Epitaxial growth was depicted with a strong in-plane and out-of plane texture: FWHM of YBCO φ-scans were 8.5° on Ni tape and 9° on IBAD Hastelloy tapes. High performances were also measured by AC susceptibility, with J_c values of 0.6 MA/cm² at 77 K (0 T) on Ni tape and close to 1 MA/cm² on IBAD substrates, with a sharp transition (ΔT_c < 0.4 K) and a T_c onset at 90 K. Deposition of 2 meter buffered YSZ and CeO₂/YBCO films have also been performed showing good in-plane alignment (φ-scan YSZ: FWHM = 11°) with a tape velocity set at 4 m/h.