Atomic surface structure of Fe3O4(001) in different preparation stages studied by scanning tunneling microscopy

We report a scanning tunneling microscopy study on the structure of the Fe3O4(001) surface on the atomic scale. The single-crystalline magnetite sample was characterized in ambient air by X-ray diffractometry and resistance versus temperature curves. Under ultrahigh vacuum condition, the sample was prepared by annealing as well as ion-sputtering. The surface was monitored by Auger-electron and photoelectron spectroscopy in order to determine the chemical composition. The atomic structure was investigated in direct space by scanning tunneling microscopy and these results were compared to the reciprocal space information gained by low-energy electron diffraction. We found different atomic surface reconstructions in all three preparation stages examined.