Voltage-induced ferromagnetism in an irradiated complex oxide

Sr-doped lanthanum manganite (La_1-xSr_xMnO₃, LSMO) is a perovskite oxide known for its rich stoichiometry-dependent phase diagram and physical properties, particularly in the context of magnetism and electrical transport. In the pristine, defect-free state, it displays a low temperature ferromagnetic metallic phase and a high temperature paramagnetic insulating phase which can be triggered thermally or by the application of electric stimulus. However, after selectively inducing defects using focused ion beam irradiation, a starkly contrasting behavior is observed. First, the metal-to-insulator transition is suppressed, and the material shows insulating behavior over the entire temperature range. Second, contrary to the metal-to-insulator transition observed in pristine LSMO, we induce an insulator-to-metal transition that shows sudden resistive switching. Third, this voltage-induced metallic phase shows the emergence of anisotropic magnetoresistance, suggesting ferromagnetic behavior in the nonequilibrium state. This work reports novel resistive switching and magnetic behavior, demonstrating the rich interplay between electronic and magnetic properties which could be employed in various emerging technologies like neuromorphic computing.