Determination of Magnetic Symmetries by Convergent Beam Electron Diffraction

TL;DR

This paper extends convergent-beam electron diffraction (CBED) to determine magnetic point groups, providing a comprehensive group classification, simulations, and guidelines for experimental application, promising a new method for magnetic structure analysis.

Contribution

It introduces a complete classification of magnetic CBED groups and maps them to magnetic point groups for all crystal orientations, expanding CBED's capabilities.

Findings

125 magnetic CBED groups constructed

Complete mapping of 122 magnetic point groups provided

Simulations confirm feasibility and accuracy

Abstract

Convergent-beam electron diffraction (CBED) is a well-established probe for spatial symmetries of crystalline samples, mainly exploiting the well-defined mapping between the diffraction groups (symmetry group of CBED patterns) and the point-group symmetries of the crystalline sample. In this work, we extend CBED to determine magnetic point groups. We construct all magnetic CBED groups, of which there exist 125. Then, we provide the complete mapping of the 122 magnetic point groups to corresponding magnetic CBED groups for all crystal orientations. In order to verify the group-theoretical considerations, we conduct electron-scattering simulations on antiferromagnetic crystals and provide guidelines for the experimental realization. Based on its feasibility using existing technology, as well as on its accuracy, high spatial resolution, and small required sample size, magnetic CBED promises to be become a valuable alternative method for magnetic structure determination.