Temperature dependences of ferroelectricity and resistive switching behavior of epitaxial BiFeO₃ thin films

We investigate the resistive switching and ferroelectric polarization properties of high-quality epitaxial BiFeO₃ thin films in various temperature ranges. The room temperature current-voltage (I-V) curve exhibits a well-established polarization-modulated memristor behavior. At low temperatures (< 253 K), the I-V curve shows an open circuit voltage (OCV), which possibly originates from the dielectric relaxation effects, accompanied with a current hump due to the polarization reversal displacement current. While at relative higher temperatures (> 253 K), the I-V behaviors are governed by both space-charge-limited conduction (SCLC) and Ohmic behavior. The polarization reversal is able to trigger the conduction switching from Ohmic to SCLC behavior, leading to the observed ferroelectric resistive switching. At a temperature of >298 K, there occurs a new resistive switching hysteresis at high bias voltages, which may be related to defect-mediated effects.