Structure and Electrical Transport Properties of Magnetite Thin Films on a MgO (100) Substrate

Using sintered -Fe2O3 as target, Fe3O4 thin films were grown on MgO (100) substrates by laser molecular beam epitaxy (L-MBE). The quality of the films was checked in situ by monitoring reflection high energy electron diffraction (RHEED) patterns during deposition, which indicate the good quality of the resulting films grown on MgO substrates. Raman spectroscopy and XPS analysis confirms the presence of single-phase Fe3O4 in surface of the films, and no other iron oxides exists. The magnetic and electrical properties of Fe3O4 thin films were investigated by PPMS-9. The results showed that resistivity of Fe3O4 thin films increases sharply below 100 K, and the Verwey tansition temperature broaden and is not distincted, which implies the existence of nonstoichiometric Fe3(1-)O4. The resistivity of Fe3O4 thin films is accorded with Sheng's tunnel model lnT-1/2 between grains.