Abstract
Multiple-beam electron microscope lattice imaging was found to be applicable to the direct analysis of crystal structures and defects in hexagonal ferrites. Numerical calculations based on the multi-slice method were made to find an optimum imaging condition suitable for the imaging of barium atom positions in hexagonal ferrites. It was shown that under the condition of nearly fixed under-focus barium atom positions are visible as bright spots in a relatively wide range of crystal thickness. The condition for the imaging was checked experimentally by the observations of M and Y compounds, and the imaging method was used for the analysis of the compositional faults introduced in the M compound. The origin of the interpretable images with the bright spot contrasts was discussed on the basis of the dynamical effect of electron scattering.
