Electrically Enhanced Exchange Bias via Solid-State Magneto-ionics

Electrically induced ionic motion offers a new way to realize voltage-controlled magnetism, opening the door generation of logic, sensor, and data storage technologies. Here, we demonstrate an effective approach magneto-ionically electrically tune exchange bias in Gd/Ni$_{1-x}$Co$_{x}$O thin films (x=0.50, 0.67), where neither layers alone is ferromagnetic at room temperature. The Gd capping layer deposited onto antiferromagnetic Ni$_{1-x}$Co$_{x}$O initiates solid-state redox reaction that reduces interfacial region oxide NiCo. Exchange established after field cooling, which can be enhanced by up 35% voltage conditioning subsequently reset with second cooling. These effects are caused presence NiCo layer, further alloys upon cooling application, as confirmed electron microscopy polarized neutron reflectometry studies. results highlight viability magneto-ionic achieve electric control bias, potentials for energy-efficient devices.