Magnetization compensation temperature and frustration-induced topological defects in ferrimagnetic anti-perovskites*

Anti-perovskites can display promising properties such as superconductivity [1] and topological band gaps [2–4]. Ferrimagnets can have many promising features, such as a so-called magnetization compensation temperature (at which the total magnetization vanishes, as a result of cancellation between magnetic moments of different sublattices) and the perpendicular magnetic anisotropy which allows robust and ultrasmall skyrmions at room temperatures [5–7]. Such features make anti-perovskite ferrimagnets very promising candidates for realizing high-density, low-cost, and energy-efficient skyrmionic device technology. 

In this work, first-principles calculations and ab-initio based Monte Carlo simulations are done to investigate magnetic properties and topological spin textures in the anti-perovskite ferrimagnet -- Mn₄N. We reveal the existence of a sizeable magnetization compensation temperature that is driven by the different temperature behaviors of three types of magnetic Mn ions when Mn₄N is in thermal equilibrium. We also report the discovery of metastable topological states, including nanometric hedgehog-anti-hedgehog pairs, that are induced by frustrated exchange interactions.

Furthermore, we look at other candidates from the Materials Project that could host similar magnetic and topological properties. Thus, we hope that this work will motivate experimental confirmations of magnetization compensation temperature and topological phases such as hedgehog-anti-hedgehog pairs in anti-perovskite ferrimagnets and will be put to use to design novel spintronic devices.