An efficient approach to characterize pseudo-merohedral twins by precession electron diffraction: Application to the LaGaO3 perovskite

作者：Ji G^*; Morniroli J P; Auchterlonie G J; Drennan J; Jacob D

来源：Ultramicroscopy, 2009, 109(10): 1282-1294.

DOI：10.1016/j.ultramic.2009.05.014

• Electron diffraction
• Precession electron diffraction
• Twin
• LaGaO3 perovskite

Pseudo-merohedral twins are frequently observed in crystals displaying pseudo-symmetry. In these crystals, many [u v w] zone axis electron diffraction patterns are very close and can only be distinguished from intensity considerations. On conventional diffraction patterns (selected-area electron diffraction or microdiffraction), a strong dynamical behaviour averages the diffracted intensities so that only the positions of the reflections on a pattern can be considered. On precession electron diffraction patterns, the diffracted beams display an integrated intensity and a "few-beam" or "systematic row" behaviour prevails which strongly reduces the dynamical interactions. Therefore the diffracted intensity can be taken into account. A procedure based on observation of the weak extra-reflections connected with the pseudo-symmetry is given to identify without ambiguity any zone axis. It is successfully applied to the identification and characterization of {121} reflection twins present in the LaGaO3 perovskite.

• 出版日期2009-9