Observation of charge ordering by X-ray anomalous scattering

Anomalous scattering technique was applied for the detection of charge orde ring of Fe3O4 and Eu3S4 at low temperatures. The energy and temperature dep endent features were clearly observed for forbidden and superlattice reflec tions in the systems. The energy-dependence curve for Fe3O4 gives a minimum intensity at E = 7.122 keV, which can be related to the valence contrast b y ion pairings. Energy dependence experiments on critical scattering have r evealed the existence of valence-ions correlation. (C) 2001 Elsevier Scienc e B.V. All rights reserved.