Electrical control of ON–OFF magnetism and exchange bias via reversible ionic motion

The lithium-based magneto-ionic effect is an emerging and promising way to control magnetism. Here, a lithium-ion battery-structure is adopted to control the magnetic properties of the Co/CoO bilayer. Using operando magnetometry, we performed a reversible toggling of lithium ion induced magnetic phase transition between nano-Co (superparamagnetism) and CoO (antiferromagnetism), which enables an ON–OFF magnetism switching. On this basis, a robust modulation of exchange bias by electric field at low temperature is achieved. In addition, reversible tuning of coercivity and magnetization up to 71% and 118%, respectively, in a Co/CoO bilayer at room temperature are performed. This work provides a more efficient means to modulate antiferromagnetism and exchange bias, facilitating the development of antiferromagnetic spintronics.