Abstract
We have observed stacking-fault pyramids (SFPs) formed as extended defects in (TBA, H)Ca
2
Nb
3
O
10
perovskite-type nanosheet aggregates (TBA = tetrabutyl-ammonium) under electron irradiation in a transmission electron microscope. Using the classical SFP as reference, characterization of the structure is discussed. However, irradiation-induced SFPs are not stable and quickly transform to loops. The formation under irradiation of SFPs rather than stacking-fault tetrahedra indicates a strong dependence of extended defect structures on the host crystal structure.