Rectifying properties of magnetite-based Schottky diode and the effects of magnetic field

摘要

Rectifying properties, with and without magnetic field, of a high quality Fe_3O_4/SrTiO_3:Nb Schottky diode have been experimentally studied. The junction exhibits an excellent rectifying behavior both below and above the Verwey temperature (T_V) of Fe_3O_4. Magnetic field has a weak but visible effect on the transport process of the junction, producing a negative magnetoresistance for T< T_V and a positive magnetoresistance for T> T_V. Based on an analysis of the current-voltage characteristics, the spin polarization of Fe_3O_4 has been deduced. It is a strong function of temperature, varying between -78% and 18%.