Understanding and tuning magnetism in layered Ising-type antiferromagnet FePSe₃ for potential 2D magnet

Recent developments in two-dimensional (2D) magnetic materials have motivated the search for new van der Waals magnetic materials. In particular, layered Ising-type magnetic materials have been intensively investigated because of their strong magnetic anisotropy which makes them a suitable candidate for 2D magnets. Fe-based MPX₃ compounds such as FePS₃ and FePSe₃ exhibit Ising-type magnetic order. However, though FePS_3­ has been well studied, FePSe₃ was overlooked for long time. In this work, we explored the magnetic properties of FePSe₃ to establish the strategies to engineer magnetic anisotropy and exchange interactions. Our study reveals distinct effects between chalcogen S and metal Mn substitutions on magnetic properties of FePSe₃. In particular, Mn substitution leads to continuous rotation of moments from out-of-plane towards the in-plane direction while moment orientation remains unchanged upon S-Se substitution. Furthermore, the magnetic ordering temperature displays non-monotonic evolution with both chalcogen and metal substitutions, which is found to be attributed to different mechanisms. This provides a better understanding of materials with Ising-type magnetism, shedding light on the study of other Ising-type magnetic systems as well as discovering novel 2D magnets for potential applications in spintronics.