Microcrack-free epitaxy of thick YBa2Cu3O7−δ films on vicinal r-cut sapphire buffered with CeO2

YBa2Cu3O7−δ (YBCO) films were fabricated by pulsed laser deposition on deliberately miscut Al2O3(11¯02) buffered with CeO2. Scanning electron microscopy observations demonstrated that 1-μm-thick YBCO films were microcrack free. Characterization of the films revealed porous morphology and high crystalline quality of YBCO with CuO planes tilted vertically and terminated frequently. These features are considered to be a contributing factor to the strain-relieving mechanism responsible for the increase in film thickness without microcracking. Microcrack-free thick YBCO films revealed Tc=90.5±0.5K, Jc(77.3K,0T)=2.0–3.0×106A∕cm2, and a substantial enhancement of Jc×t(77.3K,0T) up to 246 A/cm.