Morphology evolvement of CeO2 cap layer for coated conductors

Abstract The CeO2 cap layer were deposited on yttria-stabilized zirconia (YSZ)/Y2O3 buffered Ni–5 at.%W (Ni–W) substrate by direct-current magnetron reactive sputtering for YBa2Cu3O7−δ (YBCO) coated conductors. Morphology evolvements of CeO2 cap layers on the substrate temperature and deposition rate were investigated. Atomic force microscope exhibited the grain shape grown from granule to cluster with the temperature increasing, the grain size decreased as the sputter power increased, and their mechanisms were proposed. The root mean square surface roughness of the best sample was 1.8 nm over a 3 μm × 3 μm area. Moreover, YBCO films deposited on the CeO2/YSZ/Y2O3 buffered Ni–W substrates using pulsed laser deposition (PLD) achieved the critical current density Jc of about 1.72 MA/cm2 at 77 K and self field.