Performance Enhancement and In Situ Observation of Resistive Switching and Magnetic Modulation by a Tunable Two‐Level System of Mn Dopants in a‐Gallium Oxide‐based Memristor

Abstract Purely gallium oxide‐based memristors (GOMRs) show great potentials in resistive random‐access‐memory (RRAM) due to their chemical stability and resistive switching characteristics with R_off/R_on ratios up to 10²; indeed, GOMRs with higher R_off/R_on ratios and more functionalities are more expected. In this study, ferromagnetic amorphous gallium oxide (a‐GMO) films with a tunable two‐level system of Mn dopants, i.e., Mn²⁺ and Mn³⁺ ions, are prepared by scalable polymer assisted deposition. The Pt/a‐GMO/Pt memristors show a high R_off/R_on ratio of 10³, at least one order of magnitude higher than those of previously reported purely GOMRs, thanks to the abundant oxygen vacancies (V_Os)‐induced low resistance state and Mn²⁺‐enhanced high resistance state. Meanwhile, magnetic modulation (MM) is realized electrically in the a‐GOMRs during the RS, through the tuning of bound magnetopolarons (BMPs) by bias voltage‐induced V_Os variations, which may be useful for quaternary information coding. Notably, the transition between Mn³⁺ and Mn²⁺ions is observed in the GOMRs, which is closely related to the variations of V_O concentration and BMP amount, providing an in situ tool to probe the V_O‐induced RS and BMP‐dependent MM. The results give insights to Mn‐doped GOMRs and may be useful for design, fabrication, and testing of multifunctional high‐performance RRAMs.