High critical current density YBa2Cu3O7−δ tapes prepared by the surface-oxidation epitaxy method

YBa2Cu3O7-δ (YBCO) films with high critical current density (J c ) were successfully fabricated on nickel tapes buffered with epitaxial NiO prepared by the surface-oxidation epitaxy (SOE). To enhance the superconducting properties of the YBCO films on the SOE-grown NiO, depositions of thin oxide cap layers such as YSZ, CeO2, and MgO on Nio were investigated. These oxide cap layers were epitaxially grown on NiO. A substantially improved data of the critical temperature T c = 88K and J c = 3x105 A/cm2 (77K, 0T) and 1x104A/cm2 (77K, H//c, 4T) were obtained for YBCO film on NiO/Ni tape, by using a MgO cap layer with a thickness of 50 nm.