Epitaxial La0.5Sr0.5MnO3-delta Bipolar Memristive Devices with Tunable and Stable Multilevel States

Valence change memories are novel data storage devices in which the resistance is determined by a reversible redox reaction triggered by voltage. The oxygen content and mobility within the active materials of these devices play a crucial role in their performance. Therefore, materials which present fast oxygen migration properties and can accommodate variable oxygen stoichiometry are promising candidates. In this work, the perovskite La0.5Sr0.5MnO3-d (LSM50) as memristive material is studied, which presents a more facile oxygen vacancy formation and faster oxygen migration compared to other strontium-substituted manganites. For the first time reproducible resistive switching is reported in epitaxial LSM50-based devices with active Ti electrodes, which show large operating window and stable multilevel states. Based on the structural, chemical, and electrical results, a simple phenomenological description of the resistive switching phenomena taking place in these novel LSM50-based memristive devices is proposed.