Growth of Fe3O4(001) thin films on Pt(100): Tuning surface termination with an Fe buffer layer

We studied the preparation of well-ordered thin Fe3O4(001) films on a metallic substrate, Pt(100), using LEED and STM. The results show that film growth either by Fe reactive deposition in oxygen or by deposition-oxidation cycles onto pure Pt(100) results primarily in (111)-oriented surfaces. To grow Fe3O4(001) films, the preparation must include deposition of an Fe buffer layer as previously suggested for the growth of Fe3O4(001) on MgO(001) (Spiridis et al. Phys. Rev. B 74 (2006) 155423). Two stable (so called “dimer”- and B-layer) surface terminations were observed, both exhibiting a (√2 × √2)R450 reconstruction. Several intermediate, Fe-rich terminations were observed during the annealing process of an initially dimer-like structure. The process critically depends on the thickness of the buffer layer, which can be used as a tuning parameter for surface structures.