Room-Temperature Solid-State Nitrogen-Based Magneto-Ionics in CoxMn1−xN Films

The increasing energy demand in information technologies requires novel low-power procedures to store and process data. Magnetic materials, central to these technologies, are usually controlled through magnetic fields or spin-polarized currents that are prone to the Joule heating effect. Magneto-ionics is a unique energy-efficient strategy to control magnetism that can induce large non-volatile modulation of magnetization, coercivity and other properties through voltage-driven ionic motion. Recent studies have shown promising magneto-ionic effects using nitrogen ions. However, either liquid electrolytes or prior annealing procedures are necessary to induce the desired N-ion motion. In this work, magneto-ionic effects are voltage-triggered at room temperature in solid state systems of CoMn N films, without the need of thermal annealing. Upon gating, a rearrangement of nitrogen ions in the layers is observed, leading to changes in the co-existing ferromagnetic and antiferromagnetic phases, which result in substantial increase of magnetization at room temperature and modulation of the exchange bias effect at low temperatures. A detailed correlation between the structural and magnetic evolution of the system upon voltage actuation is provided. The obtained results offer promising new avenues for the utilization of nitride compounds in energy-efficient spintronic and other memory devices.