A unified theory of deterministic magnetic switching

The deterministic switching of magnetic order parameters is critically important, as it forms the fundamental basis for manipulating information states in magnetic memory devices. This work presents a general theoretical framework that unifies the mechanisms of magnetic switching by introducing the concept of switching symmetry and establishing that the necessary condition for deterministic switching is the breaking of all switching symmetries, which can be achieved through asymmetric states, asymmetric barriers, and asymmetric torques. Our theory can successfully and universally explain all reported experimental cases of deterministic magnetic switching and provides unified and simple design principles for new switching devices of all magnetic materials without the need of complicated simulations.