DAFS analysis of magnetite

Abstract

The mechanism of the structural transformation in Fe3O4 during its Verwey transition at 120 K is not completely understood, partly due to the lack of knowledge of the details of the local structure around different Fe atoms in the unit cell. In our experiment, this information was obtained at room temperature using Diffraction Anomalous Fine Structure (DAFS) technique which has the ability to separately solve the local structures around the octahedral and tetrahedral sites in the spinel structure of magnetite. An iterative dispersion integral algorithm was used to isolate f′ and f″ from the DAFS intensity and structural information was obtained from f″ using standard XAFS analysis methods. Relevance of our results to different models of Verwey transition is discussed.