Imaging small spinel particles in an NiO matrix

The possibility of imaging NiFe2O4 spinel particles, with a dimension of only 1–3 nm, which are embedded in an NiO matrix has been examined. Computer image simulation studies based on the multislice method and complete, atomistic models of the particle–matrix structure have been performed. The effects of double diffraction in this geometry have been investigated, and the visibility of the particles determined for four different imaging modes: centred darkfield (CDF) imaging, high‐resolution structure imaging, ‘brightfield lattice (BFL) imaging’, and ‘darkfield lattice (DFL) imaging’. It is found that, if two complementary DFL images are obtained, the smallest particle will be detectable irrespective of its position within the foil. In the presence of an amorphous layer on the sample, however, the images at certain foil thicknesses may have insufficient contrast to be detectable above the background noise. 1995 Blackwell Science Ltd