Information Technologies through Topotactic Phase Transitions

Redox memristive devices, driven by oxygen migration, offer promise for future data storage. Brownmillerite structures, like SrCoO2.5 and SrFeO2.5, enable reversible topotactic phase transitions, optimizing redox and resistive switching in memristive devices. Challenges in SrCoO2.5 thin films are addressed with atomically flat SrFeO2.5, showcasing improved performance. Epitaxial growth on [111]-oriented SrTiO3 enhances controlled oxygen ion migration, achieving high endurance and fast switching. X-ray absorption spectromicroscopy reveals the redox-based phase transition's role, and (111)-oriented devices exhibit localized transitions. SrFeO2.5 (111) devices demonstrate promising synaptic memory functionality, contributing to a neural network model with ~90% accuracy in hand-written number identification.