Functionalities of frozen domain walls in helical antiferromagnets

Abstract

Principles behind antiferromagnetic spintronics often claim that an antiferromagnet (AF) cannot be manipulated by external magnetic fields and that domain walls (DWs) are highly mobile and do not suffer strong pinning while maintaining robustness during thermal fluctuations. Using dysprosium (Dy) as an example, we take the opposite view. The functionality of a helical AF in Dy uses two intrinsic properties of chiral DWs: their intrinsic magnetization and their freezing just below the Néel temperature. Experiments with Dy single crystal show that field cooling through the fluctuation regime converts a helical AF into a domain wall–dominated system with striking properties related with robustness of frozen chiral DWs. On the other hand, chiral DWs are easily controlled by external fields throughout the fluctuation regime.