The Influence of Surface Morphology of Buffer Layer on the Critical Current Density in YBCO Coated Conductors

Abstract

1 μm-thickYBa2Cu3O7-δ(YBCO) films were grown on the Y2O3/yttria stabilized zirconia (YSZ)/CeO2buffer layers with different surface morphologies using direct-current sputtering. The critical current density (Jc) value of YBCO was 1.1 MA/cm2when the root mean square surface roughness (Rrms) of the buffer layer was 2.5 nm. As theRrmsof the buffer layer increased to 15 nm, theJcdecreased to 0.3 MA/cm2. X-ray diffraction and scanning electron microscopy showed the strong relevance of the evolution of the structure and surface morphologies of YBCO films with the buffer layer of differentRrms. A model was proposed to explain the influence of surface morphology on the superconducting properties of YBCO films.