LAUSR

Epitaxial brownmillerite SrFeO2.5 thin films were deposited on conductive Nb-doped SrTiO3 single crystal (001) and (111)-oriented substrates using pulsed laser deposition, and their resistive switching behavior was investigated. In both the (001) and (111) device configuration, the bottom SrFeO2.5/Nb:SrTiO3 interface exhibited Ohmic behavior, while the top Au/BM-SrFeO2.5 interface displayed Schottky-like contact. Unfortunately, no resistive switching behavior was observed in the (001) devices, where the oxygen vacancy channels of SrFeO2.5 are ordered along the in-plane direction of the device. Conversely, the (111)-grown SrFeO2.5 thin films with out-of-plane oriented ordered oxygen vacancy channels displayed excellent resistive switching behavior with a high on/off ratio (∼104). The discrepancies between the (001) and (111) devices were explained in terms of their oxygen dynamics and corresponding topotactic phase transition in the SrFeO2.5 switching layer.