Valence-difference contrast measurements utilizing X-ray anomalous scattering.
Anomalous scattering experiments with X-ray wavelengths close to an absorption edge have made it possible to determine independently the behaviour of ions in different valence states. The anomalous scattering factors of Fe(2+) and Fe(3+) obtained from both absorption and diffraction data have a large difference in f' between the two kinds of ions. Using a valence-difference contrast method, Bragg and diffuse scattering measurements were carried out for single crystals of Fe(3)O(4) at low temperatures. The results demonstrate the ability of the contrast method to resolve charge ordering and valence fluctuation details.