VALENCE-DIFFERENCE CONTRAST MEASUREMENTS UTILIZING X-RAY ANOMALOUS SCATTERING

Anomalous scattering experiments with X-ray wavelengths close to an ab sorption edge have made it possible to determine independently the beh aviour of ions in different valence states. The anomalous scattering f actors of Fe2+ and Fe3+ obtained from both absorption and diffraction data have a large difference inp between the two kinds of ions. Using a valence-difference contrast method, Bragg and diffuse scattering mea surements were carried out for single crystals of Fe3O4 at low tempera tures. The results demonstrate the ability of the contrast method to r esolve charge ordering and valence fluctuation details.