Spectromicroscopic insights for rational design of redox-based memristive devices

The demand for highly scalable, low-power devices for data storage and logic operations is strongly stimulating research into resistive switching as a novel concept for future non-volatile memory devices. To meet technological requirements, it is imperative to have a set of material design rules based on fundamental material physics, but deriving such rules is proving challenging. Here, we elucidate both switching mechanism and failure mechanism in the valence-change model material SrTiO 3 , and on this basis we derive a design rule for failure-resistant devices. Spectromicroscopy reveals that the resistance change during device operation and failure is indeed caused by nanoscale oxygen migration resulting in localized valence changes between Ti 4+ and Ti 3+ . While fast reoxidation typically results in retention failure in SrTiO 3 , local phase separation within the switching filament stabilizes the retention. Mimicking this phase separation by intentionally introducing retention-stabilization layers with slow oxygen transport improves retention times considerably. Memristive devices offer a future low-power solution to data storage and logic operations, but there is still a lack of suitable material design rules. Here, the authors present a design rule for retention-failure-resistant devices based on spectromicroscopic studies of strontium titanate.