Fabrication of high J/sub c/YBa/sub 2/Cu/sub 3/O//sub 7-γ/ tapes using the newly developed lanthanum manganate single buffer layers

Abstract

High J/sub c/YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// (YBCO) films have been fabricated on LaMnO/sub 3/ buffered ion-beam assisted deposition (IBAD) MgO template layers. A LaMnO/sub 3/ buffer layer is compatible with MgO surfaces and also provides a good template for growing high current density YBCO films. LaMnO/sub 3/ buffer layers were deposited using rf magnetron sputtering. On LaMnO/sub 3/-buffered-MgO [100] single crystal substrates, YBCO films with a J/sub c/ of over 4 M/cm/sup 2/ were grown using both pulsed laser deposition (PLD) and ex-situ BaF/sub 2/ process. Using PLD, J/sub c/ of 1.8 MA/cm/sup 2/ at 77 K was obtained on 200-nm-thick YBCO films grown on LaMnO/sub 3/-buffered MgO IBAD/Ni-alloy substrates. In addition, an I/sub c/ of 230 A/cm-width was obtained for 1.65-/spl mu/m-thick YBCO films grown on LaMnO/sub 3/-buffered MgO IBAD/Ni-alloy substrates using PLD at Los Alamos National Laboratory. This performance is comparable to the best single-layer results achieved on IBAD-MgO substrates.