Low-temperature structure of magnetite studied using resonant x-ray scattering

We propose a model for the Fe atomic displacements in the low-temperature phase of magnetite (Fe₃O₄), based on the analysis of the photon energy dependence of the scattered intensity of selected reflections in a resonant x-ray scattering experiment. The symmetry of the displacement pattern is forced to be consistent with the $Cc$ space group, long time claimed to be the actual symmetry of the low-temperature phase. Fe positions at octahedral sites and the corresponding charges are accounted for by a fitting procedure comparing simulations and experiment. We found a pattern of small distortions in the a-b plane. An independent sensitivity to the charge occupancy permits to refine the model of charge ordering previously proposed. Finally we have computed the electric moment of the combined charge displacements to be 1.5 μC/cm².