Influence of O2 Pressure on the Structure and Surface Morphology of YSZ Layer for YBCO Coated Conductor Deposited by PLD on Ni-W Tape

Yttria-stabilized ZrO2 (YSZ) buffer layers were prepared on Ni-5%W tapes coated with CeO2-seed layers by a pulsed laser deposition (PLD) technique. The influences of oxygen pressure on the structure and surface morphology of YSZ buffer layers for YBCO coated conductors was investigated. X-ray diffraction (XRD), scanning electron microscopy (SEM) and Atomic Force Microscope (AFM) were used to characterize YSZ films. It was found that the structure and surface morphology were sensitive to the oxygen pressure. When the O-2 pressure was higher than 1 mTorr, the YSZ film had mixed orientation and rugged surface. When the oxygen pressure was reduced to 0.5 mTorr, YSZ film had the pure (001) orientation. The surface became smooth as the oxygen pressure decreased. However, when the pressure was low to 0.1 mTorr, X-ray diffraction peaks form YSZ (002) were weak and the rough surface appeared again. The results could be explained either by plume stoichiometric changes, gas and ions interaction, or atomic rearrangement on the substrate.