Toroidicity as a route towards non-volatile quaternary memory in antiferromagnets

Magnetoelectric materials couple magnetic and electric properties and are promising candidates for future data storage applications. While a strong coupling between the two order parameters leads to cross-switchability, the separate actuation enables four different polarization states, offering prospects for a quaternary memory device, an auspicious high-density memory concept, especially in the post-Moore-law era. Here, we present a study on a bulk single-crystal of antiferromagnetic and ferrotoroidic LiNi_0.8Fe_0.2PO₄ in which a spontaneous tilt of the head-to-tail spin configuration leads to the presence of four different magnetic domains. Through Spherical Neutron Polarimetry, we deliver compelling evidence for a controlled preferential population of each of these four domains individually by applying perpendicular electric and magnetic fields. Our results suggest a new route towards the realization of high-density data storage devices based on single-phase antiferromagnetic materials.