Metastable B-doped FeNi compounds for permanent magnets without rare earths

Abstract

We apply first-principles calculations to metastable B-doped Fe-Ni compounds to compute their magnetic properties. We focus on crystal structures with tetragonal and orthorhombic lattices. Boron atoms, doped at interstitial sites, help in stabilizing noncubic Fe-Ni structures. At the same time, the dopants improve the magnetic properties, such as magnetocrystalline anisotropy, compared to FeNi alloys in the tetragonal $L{1}_{0}$-ordered structures. The calculated magnetocrystalline anisotropy constants of $1--2 \mathrm{MJ}/{\mathrm{m}}^{3}$ along with sufficient magnetic polarization saturation $(\ensuremath{\ge}1 \mathrm{T})$ show the potential of our metastable Fe-Ni-B compounds for replacing rare-earth-based magnets in permanent-magnet applications.