YBCO films grown by reactive co-evaporation on simplified IBAD-MgO coated conductortemplates

Abstract

We demonstrate coated conductors fabricated by reactive co-evaporation ofYBa2Cu3Oy (YBCO) by cyclic deposition and reaction (RCE-CDR) on ion-beam-assisted-deposition- (IBAD-)textured templates simplified by the elimination of the epitaxial buffer layer. Hastelloy substrates,both polished and unpolished, were used as a starting material for the IBAD templates.Y2O3 bed layers were then deposited followed by IBAD-textured MgO and a thin homoepitaxialMgO layer. The MgO-terminated templates were used for direct deposition ofYBCO by RCE-CDR. Critical current densities obtained for the undoped YBCOmaterial are comparable to the best values measured previously with the use ofLaMnO3 orSrTiO3 epitaxial buffer layers and state-of-the-art coated conductor results. Thestructural characterization data indicate a well oriented YBCO film witha robust template. Electrical measurements also indicate no weak links and atypical magnetic field behavior of undoped YBCO, characterized by a lowdensity of naturally occurring strong pinning centers and correlations along theab direction.