Modeling of the I-V and I-t characteristics of multiferroic BiFeO3 layers

We have investigated the current-voltage (I-V) and current-time (I-t) characteristics of Pt/BiFeO₃/SrRuO₃ structures fabricated on SrTiO₃ substrates. The devices exhibit resistive switching effect under the application of a single and multiple voltage loops. The I-V curves are simulated using a Schottky-like conduction model with voltage-varying parameters. The model includes series resistance correction and barrier lowering effect. The I-t curves are fitted using a power-law model. It is found that the Schottky barrier height (SBH) modulation arising from the BiFeO₃ polarization reversal is remarkably lower (<;0.07 eV) than previously reported (>0.5 eV) and that the ON current decay for a constant applied voltage is low and characterized by very small power exponent (~10^-2). This indicates that the ON state is remarkably stable against electrical stress.