New planar defects in Ba-deficient thin films, which had been grown onto NdGaO3 and SrTiO3 substrates by means of metalorganic chemical vapour deposition, were studied by means of high-resolution electron microscopy. The defects were associated with perturbations of the stacking sequence along the c-direction. This gave rise to structural variants with local 2:5:7, 3:4:7 or 4:6:10 cationic stoichiometries. The defects could be consistently interpreted as being CuO-YO-CuO/CuO conversions or YO/BaO (BaO/YO) interconversions in the ab-planes, which extended for a few nm along the c-axis. Structural models, based upon image matching using simulations, were proposed for 2 particular cases.

High-Resolution Electron Microscopy Investigations of Stacking Faults in YBa2Cu3O7 Metalorganic Chemical Vapor Deposited Thin Films. C.Grigis, S.Schamm, D.Dorignac: Journal of Materials Research, 1999, 14[7], 2732-8