Impulse voltage control of continuously tunable bipolar resistive switching in Pt/Bi_0.9Eu_0.1FeO₃/Nb-doped SrTiO₃ heterostructures

Epitaxial Bi_0.9Eu_0.1FeO₃ (BEFO) thin films are deposited on Nb-doped SrTiO₃ (NSTO) substrates by pulsed laser deposition to fabricate the Pt/BEFO/NSTO (001) heterostructures. These heterostructures possess bipolar resistive switching, where the resistances versus writing voltage exhibits a distinct hysteresis loop and a memristive behavior with good retention and anti-fatigue characteristics. The local resistive switching is confirmed by the conductive atomic force microscopy (C-AFM), suggesting the possibility to scale down the memory cell size. The observed memristive behavior could be attributed to the ferroelectric polarization effect, which modulates the height of potential barrier and width of depletion region at the BEFO/NSTO interface. The continuously tunable resistive switching behavior could be useful to achieve non-volatile, high-density, multilevel random access memory with low energy consumption.