Topotactic Phase Transition Driving Memristive Behavior
Nallagatla, Heisig, Baeumer, Feyer, Jugovac, Zamborlini, Schneider, Waser, Kim, Jung, Dittmann (2019) Topotactic Phase Transition Driving Memristive Behavior Adv Mater (IF: 29.4) 31(40) e1903391Abstract
Redox-based memristive devices are one of the most attractive candidates for future nonvolatile memory applications and neuromorphic circuits, and their performance is determined by redox processes and the corresponding oxygen-ion dynamics. In this regard, brownmillerite SrFeO2.5 has been recently introduced as a novel material platform due to its exceptional oxygen-ion transport properties for resistive-switching memory devices. However, the underlying redox processes that give rise to resistive switching remain poorly understood. By using X-ray absorption spectromicroscopy, it is demonstrated that the reversible redox-based topotactic phase transition between the insulating brownmillerite phase, SrFeO2.5 , and the conductive perovskite phase, SrFeO3 , gives rise to the resistive-switching properties of SrFeOx memristive devices. Furthermore, it is found that the electric-field-induced phase transition spreads over a large area in (001) oriented SrFeO2.5 devices, where oxygen vacancy channels are ordered along the in-plane direction of the device. In contrast, (111)-grown SrFeO2.5 devices with out-of-plane oriented oxygen vacancy channels, reaching from the bottom to the top electrode, show a localized phase transition. These findings provide detailed insight into the resistive-switching mechanism in SrFeOx -based memristive devices within the framework of metal-insulator topotactic phase transitions.© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Links
http://www.ncbi.nlm.nih.gov/pubmed/31441160http://dx.doi.org/10.1002/adma.201903391
