Reel-to-reel deposition of epitaxial double-sided Y2O3 buffer layers for coated conductors

Y2O3 films were deposited on both sides of biaxially textured Ni–5 at.%W substrates by reel-to-reel DC. magnetron reactive sputtering, serving as a seed layer for high performance coated conductors. The deposition parameters, such as water vapor pressure, substrate temperature and sputtering power, were systematically studied. The YSZ layer and CeO2 layer were fabricated on Y2O3 buffered Ni–W tapes using the same deposition system. X-ray diffraction analysis confirmed that optimized double-sided CeO2/YSZ/Y2O3 buffer layers showed a significant improvement in in-plane and out-of-plane texture. Atomic force microscope revealed a smooth, dense and crack-free surface morphology. YBa2Cu3O7-δ films grown on double-sided CeO2/YSZ/Y2O3 buffered Ni–W tapes by D.C. sputtering exhibited a critical current density of 1.26 MA/cm2 at 77 K for each side.

► We reported a promising double-sided buffer structure for YBCO coated conductors. ► The FWHM values of the ω-scans were 3.1° and 3.7° for side A and B of the Y2O3 seed layer. ► The FWHM values of the (1 1 1) ϕ-scan of Y2O3 layer in the double-sided buffer layer are 4.8°. ► Typical double-sided YBCO layer exhibited a Jc of 1.26 MA/cm2 at 77 K, for each side.