Surface reconstruction of Fe3O4(100)

Preliminary results of low-energy ion scattering (LEIS) and low-energy elec tron diffraction (LEED) studies of Fe3O4(100) are presented. Thin epitaxial Fe3O4(100) films were grown by O-2-assisted molecular beam epitaxy (MBE) o f Fe on a MgO(100) substrate. LEED measurements revealed a (root 2 x root 2 )R45 reconstruction pattern as has already been reported in the literature. The surface structure on an atomic scale was studied by LEIS. The sample s urface was bombarded with 3 or 6 keV A(+) ions in a grazing-angle geometry, and azimuthal scans of the yields of the recoiled Fe and O atoms emitted a t scattering angles of 37 degrees and 53 degrees were measured. The scans w ere analyzed by performing computer simulations of the scattering and recoi ling of atoms for a number of trial models. We confirm the presence of two mutually perpendicular structural domains at the surface of the films frown . Bulk Fe3O4. contains Fe atoms in tetrahedral and octahedral positions. Th e surface was found to be terminated by tetrahedral Fe atoms. Further detai ls of the atomic arrangement and surface relaxation were studied. (C) 2000 Elsevier Science B.V. All rights reserved.