Graphene Quantum Dots as an Oxygen Reservoir for Topotactic Phase Transition‐Based Memristive Devices

Abstract A novel class of transition metal oxides, capable of reversible topotactic phase transition between the oxygen‐deficient brownmillerite and oxygen‐rich perovskite, has emerged as a promising material for memristive and magnetoelectric devices. However, the absence of a local oxygen source in the device structure necessitates an oxygen exchange process between the surrounding atmosphere and the switching layer during operation, which can lead to unreliable device performance. In this study, graphene quantum dots (GQDs) are introduced into a SrFe 0.5 Co 0.5 O x memristive device as an oxygen reservoir for the nanoscale topotactic redox process. The SrFe 0.5 Co 0.5 O x memristive devices with GQDs exhibit reliable resistive switching performance compared to SrFe 0.5 Co 0.5 O x devices without GQDs. To understand the effect of GQDs on the device structure, a pulse endurance test is carried out in a high vacuum. The devices with GQDs show rather good endurance behavior, while devices without GQDs exhibit endurance failure. These results provide a deeper understanding of the potential use of GQDs in enhancing the performance of SrFe 0.5 Co 0.5 O x memristive devices, with implications for tuning nanoscale topotactic phase transition for multi‐functional properties.