Epitaxial growth of heterostructures on biaxially textured metallic substrates for YBa2Cu3O7-x tape fabrication

The paper presents the current status of Ente per le Nuove tecnologie, l'En ergia e l'Ambiente research on the processing of high-irreversibility-field superconductor YBa2Cu3O7-x (YBCO) tapes, useful for power application. A m ajor part of this review is concerned with buffer layer growth, because thi s is the most important stage in the YBCO thick-film fabrication on biaxial ly textured metallic substrates. Several architectures are presented: CeO2/ Pd/Ni, CeO2/(Ni-V) and CeO2/NiO/(Ni-V). For all the buffer layer structures the top CeO2 film was deposited by pulsed-laser deposition, while the Pd f ilm was grown by electron-beam evaporation. The observed epitaxial orientat ion is [001]. The properties of a new non-magnetic Ni-V alloy substrate, as well as the preliminary results on superconducting multilayer structures, are also presented. The YBCO film grown on the CeO2/NiO/(Ni-V) configuratio n has the critical temperature T-c onset of 90.9 K, zero resistance at 86 K and the critical current density J(c) = 10(5) A cm(-2) at 77 K and in zero magnetic field.