Pulsed laser deposition of YBCO thin films on IBAD–YSZ substrates

High-quality YBa₂Cu₃O_7−x (YBCO) films were fabricated on yttria-stabilized zirconia (YSZ)-buffered Hastelloy C276 substrates by pulsed laser deposition. YSZ was grown by ion-beam-assisted deposition. A thin (≈10 nm) CeO₂ layer was deposited before the deposition of YBCO. The crystalline structure and biaxial texture of the YBCO film and the buffer layer were examined by x-ray diffraction 2θ-scan, ϕ-scan and pole-figure analysis. Epitaxial growth of the YBCO film on the buffer layer was observed. Full width at half maximum (FWHM) value of 7.4° was measured from the ϕ-scan of YBCO(103). Raman spectroscopy showed compositional uniformity and phase integrity in the YBCO films. Surface morphologies of the YBCO films were examined by scanning electron microscopy. Comparative studies indicated that the CeO₂ buffer layer significantly improves the structural alignment and superconducting properties of YBCO films. T_c = 90 K, with sharp transition, and transport J_c = 2.2 × 10⁶ A cm⁻² at 77 K in zero-external field were obtained on the 0.5 μm thick YBCO films. The dependence of J_c on the FWHM of the YBCO(103) ϕ-scan indicated that high J_c is associated with low FWHM.