Interfacial characteristics of a Fe3O4∕Nb(0.5%):SrTiO3 oxide junction

The temperature dependent Schottky diode characteristics of epitaxial junctions between Nb:SrTiO3 (Nb concentrations: 0.5%) and Fe3O4 are studied. Epitaxial thin films of Fe3O4 were grown on Nb:SrTiO3 substrates by pulsed laser deposition technique. The films and heterointerfaces were characterized by x-ray diffraction, Z-contrast transmission electron microscopy, magnetic susceptibility, four-probe in-plane resistivity, and the temperature dependent junction current-voltage (I‐V) characteristics. The nonlinear nature of the characteristics is analyzed within the framework of thermionic emission theory. Junction parameters such as the Schottky barrier height (ϕB) and ideality factor (η) are extracted. The temperature evolution of these parameters shows interesting and systematic trends, with remarkable changes near the Verwey transition (TV=120K). The magnetic field dependence of I‐V characteristic data is also recorded and a spin polarization of ∼80% is estimated for the magnetite electrode.