Response of the Verwey transition in magnetite to controlled point-like disorder induced by 2.5 MeV electron irradiation
Controlled point-like disorder induced by low temperature 2.5 MeV electron irradiation was used to probe the nature of the Verwey transition in magnetite, Fe3O4. Two large single crystals, one with optimal transition temperature, TV ≈ 121 K, and another with TV ≈ 109 K, as well as magnetite magnetosome nanocrystals harvested from the lysed cells of the marine magnetotactic vibrio Magnetovibrio blakemorei strain MV-1, TV ≈ 110 K, were examined. Temperature-dependent resistivity is consistent with the semiconductor-to-semiconductor (insulator) sharp, step-like Verwey transition from a state with a small bandgap of around 60 meV to a state with a large bandgapmore »