Differential phase contrast imaging in the scanning transmission electron microscope has long been used to map out magnetic domain structure in materials [1-3] and more recently to probe electric field structures [4-6]. However, artefacts from diffraction contrast can hinder both quantitative and qualitative interpretation of electromagnetic field maps [7-9].
Recent preliminary results show that precession – the averaging of the recorded signal over a range of relative angles between the electron probe and the specimen – can significantly suppress confounding diffraction contrast artefacts [10]. In this talk we use Bloch wave simulations to explore both the potential for diffraction contrast artefacts and the extent to which precession is able to suppress them. This includes examining the angular range over which precession is performed and assessing the relative contributions of sample bending and thickness variation to diffraction contrast artefacts.
This research was supported under the Australian Research Council Discovery Projects funding scheme (Project No. DP160102338).