Three-Dimensional Observation of Superlattice Domains in Ordering Alloys by DFTEM Tomography

This paper shows a technique to acquire a tilt series of dark-field transmission electron microscopy (DFTEM) images for superlattice domains formed in ordering alloys. Fundamental points are as follows 1) use of a superlattice reflection with a relatively long extinction distance (small structure factor) to satisfy the projection requirement and 2) careful realignment of the electron beam to keep the diffraction condition during tilting the specimen. Tomographic reconstruction from the obtained DFTEM tilt series visualizes three-dimensional morphology and distribution of the superlattice domains, demonstrating the feasibility of the DFTEM tomography.