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

Fe3O4(001)films onFe(001): Termination and recons

“…The oval statistics over 2500 nm 2 taken for many terraces and samples gives the average occupation of 0.50± 0.03 oval per the unit cell of the ͑ͱ2 ϫ ͱ 2͒R45°reconstruction. The ovals, apart from their densities, are very similar to the shapes observed by Tarrach et al 5 and Gaines et al 9 for single-crystalline and thin-film surfaces, respectively. Gaines et al 9 described them as diffused clusters of atoms, which may consist of both tetrahedral and octahedral Fe ions, and are difficult to interpret due to a complicated atomic arrangement.…”

“…They reveal elongated shapes forming a square 8.4 Å ϫ 8.4 Å mesh, interpreted as clusters of atoms within the tetrahedral termination. 5,9 To our knowledge, images of the empty and filled states have never been observed for the same sample with the ͑ͱ2 ϫ ͱ 2͒R45°reconstruction.…”

“…The structure of the ͑001͒ magnetite surface has been intensively studied for single crystals 2,[5][6][7][8] as well as for epitaxial films. [9][10][11][12][13][14][15] The surface is usually discussed as being composed of atomic sublayers, containing either only tetrahedral iron ions Fe͑A͒ ͑the so-called A layer͒ or oxygen and octahedral iron ions Fe͑B͒ ͑the so-called B layer͒.…”

Surface chemistry and catalysis on well-defined epitaxial iron-oxide layers

“…Other orientations have to be prepared by the usual procedure of cutting, polishing, sputtering and annealing in vacuum or in O 2 atmosphere. Many metal-oxide surfaces have been prepared in this way as reviewed in [4][5][6], also among these are several surface planes of Fe 3 O 4 and α-Fe 2 O 3 single-crystals [135][136][137][138][139][140][141]. However, single-crystal samples may cause several experimental problems.…”

Molecular-Level Processes Governing the Interaction of Contaminants with Iron and Manganese Oxides

“…A guiding principle that can be used to predict surface termination is that of surface autocompensation, which states that the most stable surface(s) is (are) those for which the cation (anion)-derived dangling bonds are completely empty (full) (Gibson and LaFemina 1996). Both of the aforementioned terminations of Fe 3 O 4 (001) can be made to be autocompensated-model A by removal of every other tetrahedral iron(III) cation (Tarrach et al 1993) and model B by creation of oxygen vacancies and modification of octahedral iron oxidation states (Voogt 1998). Both surfaces predict a (• 2x• 2)R45° surface reconstruction, which is observed The second most important set of surface structural parameters is the interlayer relaxations that result from creating the surface in the first place.…”