Ferroelectric resistance switching in Pt/Fe/BiFeO3/SrRuO3/SrTiO3 heterostructures
The BiFeO3 (BFO)-based heterostructures have been widely studied to develop the high-speed, high-density and low-consumption nonvolatile memory. In this work, the resistive switching (RS) behavior in the metal/BFO/SrRuO3(SRO) heterostructures was investigated. The I–V curves in the Pt/Fe/BFO/SRO and Pt/BFO/SRO heterostructures demonstrate that the RS behavior in the Pt/Fe/BFO/SRO heterostructures results from the ferroelectric polarization modulated the depletion layer width around the BFO/SRO interface. According to the fitting results of the I–V curves, the conductivity mechanisms are the interface-limited Fowler-Nordheim tunneling mechanism in the negative bias and the space-charge-limited-conduction mechanism in the positive bias. Compared with the memory performance in the Pt/BFO/SRO heterostructures, the memory performance in the Pt/Fe/BFO/SRO heterostructures evidently improves. The Fe layer with the similar work function of the BFO layer can decrease the barrier height and reduce the accumulation of the injected charges at the top-electrode/BFO interface, which further improves the ferroelectric performance of the BFO layer.