Resistive switching in Pt/BiFeO3/SrRuO3/SrTiO3 heterostructures.

The demand for high speed, high storage density, and low power consumption nonvolatile memory technology has stimulated extensive research into new functional materials. Resistive switching has been reported in multiferroic bismuth ferrite (BFO), in which the resistance can be switched between a high resistance state (IIRS) and a low resistance state (LRS) [ 1-2 ]. These two resistance states can stand for binary 0 and 1 in resistive -switch memory. In general, the metal/BFO/metal cell shows bipolar resistive switching that the set to a LRS occurs at one voltage polarity and the reset to the FIRS appears at reversal voltage polarity. It has been widely recognized that this so-called bipolar resistive switching is usually connected with a voltage-driven oxygen vacancy movement.However, BFO films exhibit p-type conduction as a result of Bi loss[ 3 ], and a Schottky junction or a p-n junction may be formed at the metal/BFO interface and can be modulated by the ferroelectric polarization, which induces blocking or non -blocking interfaces for the transport of carriers and consequent the resistive switching behavior [ 4-5 ]. Here, we prepared PVBFO/SrRuO 3 /SrTiO 3 resistive device units and observed a repeatable and switchable resistive effect of BFO films with a tunable HRS/LRS ratios and a low resistance switching voltage of ±1.5 V, apart from the high forming voltage.