Observation of two in-plane epitaxial states in YBa2Cu3O7−δ films on yttria-stabilized ZrO2

Abstract

We demonstrate that two distinctly different in-plane epitaxial states of c-axis oriented YBa2Cu3O7−δ (YBCO) films on (100) yttria-stabilized ZrO2 (YSZ) single-crystal substrates can be produced independently, namely, YBCO [100]//YSZ [100] or YBCO [100]//YSZ [110]. Both in-plane epitaxial relationships can be modeled by matching YBCO and YSZ oxygen sublattices at the film-substrate interface. High critical current densities (Jc), ∼5×105–1×106 A/cm2 at 77 K, are achieved when ≳90 vol % of either orientation is present. Jc can be degraded nearly four orders of magnitude in films with mixed orientation.