Defect Structure of Laser Deposited Y-Ba-Cu-O Thin Films on Single Crystal MgO Substrate

Structural defects in thin films of nominal composition YBa2Cu3O7 (123) grown on single crystal MgO have been characterized. The main types of stacking defects correspond to the cationic stoichiometries of “248”, “247”, and “224”. Several types of edge dislocations have been observed. Due to the frequent changes in the stacking sequence, antiphase boundaries are created to accommodate the misfit across regions in which the repeat sequence is not identical. The films exhibit a mosaic microstructure due to the formation of grain boundaries in the a-b plane. © 1990, Materials Research Society. All rights reserved.