A comparison of [001] low-angle tilt grain boundaries of (100) and (110) grain boundary planes in YBa2Cu3O7-delta coated conductors

The microstructure and grain boundary structure in YBa2Cu3O7-delta (YBCO) t hick film coated conductors are characterized by transmission electron micr oscopy. The films contain low-angle [001] tilt grain boundaries with period ic arrays of edge dislocations parallel to the c-axis. A majority of the gr ain boundary planes are of either the (100) or the (110) type. Grain bounda ry dislocations (GBDs) with a [100] Burgers vector were observed in tilt bo undaries with (100) boundary planes. However, partial dislocations, separat ed by stacking faults, were found at boundaries with near (110) grain bound ary planes. Extensive g . b and g . R analyses confirmed the partials to be of 1/2[110] type. These results suggest that the characteristics of disloc ation structures, which have been proposed in various grain boundary-based flux-pinning models, depend not only on the misorientation angle theta, but also on the types of grain boundary plane. The effect of dissociated GBDs on the transport properties of low angle grain boundaries in YBCO coated co nductors is discussed. (C) 2001 Elsevier Science B.V. All rights reserved.