Ferromagnet-like binary switching of a Stoner-Wohlfarth antiferromagnet

The Stoner-Wohlfarth antiferromagnet (AFM), an extension of the classical Stoner-Wohlfarth model originally describing the magnetization reversal in ferromagnetic nanoparticles^1,2, refers to a single-domain AFM whose Néel vector can be coherently switched by the magnetic field. These AFMs not only retain the inherent advantages of antiferromagnetism but also feature controllable Néel vector and a perfect switching ratio, thus emerging as promising building blocks for ultradense magnetic memories and high-throughput computing systems^3,4. However, bulk AFMs are not the Stoner-Wohlfarth AFMs owing to the hard-to-switch Néel vector and inevitable multidomain structure^3,5-7. Here we report that CrPS₄, a two-dimensional (2D) van der Waals (vdW) A-type AFM, exhibits ideal characteristics of the Stoner-Wohlfarth AFMs, because of the dominance of antiferromagnetic exchange over the magnetic anisotropy and high quality of vdW interfaces. The antiferromagnetic order undergoes a ferromagnet (FM)-like binary switching with the magnetic field rather than the layer-by-layer flipping observed in other 2D A-type AFMs. Moreover, we deduce the characteristic exchange length of several vdW A-type AFMs and propose a criterion for judging the Stoner-Wohlfarth AFMs. Our work therefore establishes a universal framework for understanding the magnetization reversal in layered AFMs and promotes the effective use of 2D AFMs in advanced spintronic devices.