A Unified Theory of Magnetic Switching

In spintronics, the deterministic switching of the magnetic order parameter is essential for distinguishing "1" and "0" information states in next-generation memory devices. This study presents a unified theoretical framework to analyze the switching behavior in magnetic systems. We propose the concept of switching symmetries, which are spontaneously broken due to magnetic ordering within the Landau phase transition theory. Since these symmetries connect degenerate magnetic ground states, their breaking via external stimuli is key to enabling deterministic switching, which can be achieved through asymmetries in states, barriers, or torques. Using a macrospin modeling approach, we explore how external stimuli break these symmetries to facilitate deterministic switching. The proposed theory and modeling results are substantiated by successfully explaining 180° switching behaviors in both ferromagnetic and antiferromagnetic materials.