Ja. Alarco et al., MICROSTRUCTURE OF AN ARTIFICIAL GRAIN-BOUNDARY WEAK-LINK IN AN YBA2CU3O7-DELTA THIN-FILM GROWN ON A (100)(110), [001]-TILT Y-ZRO2 BICRYSTAL, Ultramicroscopy, 51(1-4), 1993, pp. 239-246
The microstructure of an artificial grain boundary in an YBa2Cu3O7-del
ta (YBCO) thin film grown on a (100)(110), [001]-tilt yttria-stabilize
d-zirconia (YSZ) bicrystal substrate has been studied using transmissi
on electron microscopy (TEM). The orientation relationship between the
YBCO film and the YSZ substrate was [001]YBCO parallel-to[001]YSZ and
[110]YBCO parallel-to[100]YSZ for each half of the bicrystal film. Ho
wever, the exact boundary geometry of the bicrystal substrate was not
transferred to the film. The substrate boundary was straight while the
film boundary was wavy. In several cases there was bending of the lat
tice confined within a distance of a few basal plane lattice spacings
from the boundary plane and microfaceting. No intergranular secondary
phase was observed but about 25% of the boundary was covered by c-axis
-tilted YBCO grains and a-axis-oriented grains, both of which were typ
ically adjacent to CuO grains or surrounded by a thin Cu-rich amorphou
s layer.