An investigation on low operating voltage induced self-rectifying multilevel resistive switching in AgNbO₃

This study presents a resistive random-access memory (RRAM) based on silver niobate (AgNbO₃) perovskite films prepared via sputtering for the first time. The device exhibits a self-rectifying behavior at low operating and switching voltages, with a set voltage of about −0.4 V. Bipolar resistive switching was realized at a low operating voltage and with small set and reset voltage distributions. Compared to previously reported resistive switching perovskite materials, the device displays a superior resistive switching capability while maintaining a uniform memory window of up to 10², excellent endurance of over 10⁴ cycles, and a long retention period of over 10⁶ s. Moreover, the RRAM device exhibits four levels of resistive switching when the compliance current is varied, with each level of resistance state demonstrating uniformity and discrete read windows. The carrier-transport mechanism of the device was elucidated by considering various conduction mechanisms, including Schottky emission and space-charge-limited conduction. The resistive switching behavior was found to follow the conductive filamentary model, which is governed by the migration of oxygen vacancies when an electric field is applied. These outstanding properties of AgNbO₃ make it a promising perovskite material option for future nonvolatile multilevel RRAM device applications.