Scanning tunneling spectra and low energy ion scattering studies of the Verwey transition in MBE Fe3O4 (100) thin film

The (100) surface of magnetite Fe3O4 thin film was studied by a UHV low-tem perature scanning tunneling microscope and by an ion scattering spectroscop y. The tunneling spectra revealed a widening of the gap with decreasing tem perature, which may be related to the metal-insulator phase transition in t his material. A strong effect of this phase transition on ion scattering fr om such a surface was observed. The temperature dependence of the scattered ion yield, R+(T), revealed two minima at around 100 K and at 125 K under N e+ bombardment with the primary energy up to 6 keV. The disappearance of th e high-temperature minimum at a bombarding energy of 6.5 keV gave a further evidence for the ion velocity dependence of the character of the R+(T) cur ve, which has been first observed for a MBE Fe3O4 (111) film surface.