Stability and magnetism of FeN high-pressure phases

Abstract

Experimentally discovered compounds in the iron-nitrogen system belong to the low concentration part of the Fe-N phase diagram. In our paper, which is based on ab initio calculations we have studied formation and stability of high-pressure iron mono-nitride phases, and particularly the new magnetic phase with a NiAs-type structure. We have investigated the role of dynamic, thermodynamic and electronic properties, such as electronic correlations and pressure-induced phase stabilisation. We demonstrate that the new hexagonal FeN phase is stable for a wide range of external pressure and it can be formed as a metastable phase at zero pressure. We show that it has relativity small Curie temperature and it may possess a non-collinear magnetism.