OBSERVATION OF 2 INPLANE EPITAXIAL STATES IN YBA2CU3O7-DELTA FILMS ON YTTRIA-STABILIZED ZRO2

We demonstrate that two distinctly different in-plane epitaxial states of c-axis oriented YBa2Cu3O7-delta (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 (J(c)), approximately 5 X 10(5)-1 X 10(6) A/cm2 at 77 K, are achieved when > 90 vol % of either orientation is present. J(c) can be degraded nearly four orders of magnitude in films with mixed orientation.