Abstract
The pre-edge peak as well as the main peak just above the Fe K-absorption edge is observed for anisotropic tensor of susceptibility (ATS) scattering in magnetite, Fe3O4 (inverse spinel structure). In order to investigate the origin of the peaks, we study the ATS scattering in franklinite, ZnFe2O4 (normal spinel structure) which has Zn atoms in the tetrahedral A sites and Fe atoms in the octahedral B sites. In franklinite, only the main ATS peak is observed at almost the same energy as magnetite. Therefore, the pre-edge and main peaks of magnetite originate from the A and B site atoms, respectively. Because the dipole transition of A site atoms cannot excite ATS scattering, the dipole-quadrupole transition is investigated. The observed energy spectra for the (002) and (006) reflections in magnetite reveal that the pre-edge peak is due to the dipole-quadrupole transition of Fe atoms in the A sites. Comparing the main peak intensities of both reflections in magnetite and franklinite, we conclude that the main peak in franklinite is caused by dipole transition of the B site atoms. However the contribution of dipole-quadrupole transition is presumed in magnetite.
