Fundamental Requirements for Deterministic Magnetic Switching

Determine the fundamental requirements for deterministic switching in magnetic systems, defined as the ability of controllable external stimuli to unambiguously drive the system from any initial state to a uniquely designated final state.

Background

Deterministic switching of magnetic order parameters underpins information manipulation in spintronic devices. While ferromagnets allow magnetization reversal via magnetic fields or current-induced torques, antiferromagnets and altermagnets pose greater challenges due to their compensated magnetic moments, making electrical control of the Néel vector difficult and demonstrated only in limited material systems.

Historically, the field lacked a unified understanding of what physical and symmetry conditions are required to guarantee deterministic switching to a unique final state. This paper introduces the concept of switching symmetry and argues that breaking all switching symmetries connecting desired and undesired ground states is a necessary condition, supported by analysis of the Landau–Lifshitz–Gilbert dynamics and case studies in ferromagnets, antiferromagnets, and altermagnets.