Resistive hysteresis and capacitance effect in NiFe2O4/SrTiO3: Nb(1wt%) junctions

Abstract Epitaxial ultrathin NiFe 2 O 4 films were deposited on 1 wt% Nb-doped SrTiO 3 (0 0 1) substrates by reactive cosputtering to form junctions with an area of ∼2 mm 2 , and current–voltage curves show rectifying and asymmetrical hysteresis characteristics. The resistance calculated from the current–voltage curves is strongly voltage dependent, and the hysteretic loops with high and low resistive states were observed. The hysteretic loops are considered to stem from the capacitance effect of the highly resistive NiFe 2 O 4 layer, which leads to charge accumulation at the interfaces. The results show that the interfaces of the junctions have a large areal capacitance of ∼100 nF/mm 2 from 300 to 120 K.