Electronic properties of half metallic Fe3O4 films

A systematic study of the electronic properties of Fe3O4 films grown directly on Si(001) substrates and on Ta, Ti, and SiO2 buffer layers using electron beam deposition is presented. The effect of the buffer layer on the Verwey transition temperature and on the current–voltage characteristics of Fe3O4 has been studied in detail. We observed that for a fixed Fe3O4 film thickness, the Verwey transition temperature is strongly dependent on the buffer layer materials. Transmission electron microscopy reveals that the growth mechanism of the Fe3O4 films is strongly dependent on the type of buffer layer used. The contribution of long range and short range charge ordering below the transition temperature has also been investigated. We observed an insulator-like gap structure in the density of states below the transition temperature which gradually disappears with increasing temperature.