Voltage control of magnetism has been considered and proven to be an efficient actuation protocol to boost energy efficiency in a widespread range of spintronic devices. In particular, the study of voltage-induced changes in magnetism by the magneto-ionic effect has rapidly accelerated during the past few years due to the versatile advantages of effective control, non-volatile nature, low-power cost, etc. In this perspective, we briefly outline the recent research progress on the voltage-controlled magneto-ionic effect by using two representative dielectric gating materials [ionic liquids (ILs) and ionic conductors] in different functional solid-state heterostructures and devices, mainly including both the ferroic-order [ferromagnetic, ferroelectric (FE), and multiferroic] oxides and magnetic metal-based heterostructure systems. Within the framework of ferroic oxide heterostructures, we have also extended the IL control to FE materials, clarifying that FE properties can also be tailored by electrostatic and electrochemical methods. Finally, we discuss the challenges and future aspects of magneto-ionics, which would inspire more in-depth studies and promote the practical applications.
