The geometry and interfaces due to ordering and their observation in transmission electron microscopy and electron diffraction

Single crystals in the operational sense of the word are often fragmented into "domains", resulting from a phase transformation. In this paper we first present a review of the contrast effects observed in the electron microscope and which allow to study the geometry of the interfaces between such domains. Subsequently we discuss a number of phenomena which give rise to domain formation. In a third part we present a number of case studies illustrating different aspects of domain formation.