Mechanism analysis of phase-change-induced negative differential resistance in BiFeO₃/La₀.₇Sr₀.₃MnO₃ heterojunction-based resistive switching memory devices

Perovskite oxide heterostructures are promising candidate materials for advanced electronic devices, particularly in the fields of resistive switching memory and neuromorphic computing. This paper investigates the fabrication and characterization of a resistive switching memory device based on a BiFeO₃/La_0.7Sr_0.3MnO₃ heterostructure, which is prepared using radio frequency magnetron sputtering. Through phase transition induction, the device exhibits significant resistive switching (RS) behavior accompanied by a notable negative differential resistance (NDR) effect at room temperature. Experiments reveal that the unannealed sample shows a significant NDR effect and stable bipolar RS characteristics (ON–OFF ratio ∼10²) under ±4.5 V bias, while the performance of the device annealed at 500°C significantly degrades (ON–OFF ratio decreases to ∼10⁰). The formation of oxygen vacancy conductive filaments at the BiFeO₃/La_0.7Sr_0.3MnO₃ interface in the unannealed sample can explain the emergence of the NDR effect; while annealing treatment leads to a reduction in oxygen vacancies, disrupting the dynamic regulation capability of phase transition-driven conductive filaments.