A new method was described for analyzing antiphase domains using high-resolution electron micro-graphs. A high-resolution electron microscopic image, taken at a zone axis, was treated as the sum of many sets of interference fringes. The analysis then furnished information concerning variations in the image periodicities as a function of position. In particular, the amplitude and phase variations of these fringes were separately analyzed. The amplitude images revealed the antiphase boundaries in a similar manner to conventional dark-field techniques, while the phase produced images of the translation domains and defined the associated translation vectors. The phase variations could also be related to the strain field that was associated with the corresponding lattice planes. Experimental images of antiphase boundaries in Cu3Au, taken at [001], were used to demonstrate the technique. Antiphase boundaries which were perpendicular and parallel to the electron beam were characterized. The phase images were used to characterize disordered regions in which the domains were too small to be analyzed by using dark-field methods. A quantitative criterion was proposed for distinguishing between a structural model that was based upon homogeneous short-range order, and a model that was based upon micro-domains. In the present experimental case, it was shown that the image contrast could not be explained only in terms of homogeneous short-range order. A micro-domain type of model was more appropriate.

Geometric Phase Analysis of High-Resolution Electron Microscopy Images of Antiphase Domains M.J.Hÿtch, L.Potez: Philosophical Magazine A, 1997, 76[6], 1119-38