Stacking-fault pyramids, formed as extended defects in (TBA,H)Ca2Nb3O10 perovskite-type nanosheet aggregates (TBA = tetrabutyl-ammonium) under electron irradiation in a transmission electron microscope, were observed. Characterization of the structure was carried out by using the classical stacking-fault pyramids as reference. However, irradiation-induced stacking-fault pyramids were not stable and quickly transformed into loops. The formation under irradiation of stacking-fault pyramids rather than stacking-fault tetrahedra indicated a strong dependence of extended defect structures on the host crystal structure.

Stacking-Fault Pyramids Formed in Perovskite-Type Niobate Nanosheet Aggregates under Electron Irradiation. F.F.Xu, Y.Bando, Y.Ebina, T.Sasaki: Philosophical Magazine Letters, 2003, 83[6], 367-73