A single oxide buffer layer on a cube-textured Ni substrate for the development of YBCO coated conductors by photo-assisted MOCVD

Large-scale commercial applications of high-temperature superconducting (HTS) YBa₂Cu₃O_7-x (YBCO)-based second generation coated conductors require simple and cost-effective process technologies to fabricate the buffer layer(s) and YBCO superconducting layer. Sm_0.2Ce_0.8O_2+x (SCO) thick films have been epitaxially deposited on roll-textured Ni substrates as the single buffer layer for HTS coated conductors by using high-rate photo-assisted metal-organic chemical vapour deposition (PhAMOCVD) at a relatively low deposition temperature of 600 °C. YBCO superconducting films were then successfully deposited on these thick SCO single buffer layers by the same high-rate PhAMOCVD process, and yielded critical current densities (J_c) of ∼0.52 MA cm^-2 at 77 K and zero applied field. X-ray diffraction and scanning electron microscope analyses of SCO/Ni samples revealed very good crystalline structure and surface morphology for the SCO single buffer layers. These results suggest that SCO single buffer layer, as well as the YBCO conductors, fabricated by the high-rate PhAMOCVD technique may offer great potential for manufacturing YBCO coated conductors.