Impact of local arrangement of Fe and Ni on the phase stability and magnetocrystalline anisotropy in Fe-Ni-Al Heusler alloys

Abstract

On the basis of density functional calculations, we report on a comprehensive study of the influences of atomic arrangement and Ni substitution for Al on the ground state structural and magnetic properties for Fe${}_2$Ni${}_{1+x}$Al${}_{1-x}$ Heusler alloys. We discuss systematically the competition between five Heusler-type structures formed by shuffles of Fe and Ni atoms and their thermodynamic stability. All~Ni-rich Fe${}_2$Ni${}_{1+x}$Al${}_{1-x}$ tend to decompose into a dual-phase mixture consisting of Fe${}_2$NiAl and~FeNi. The~successive replacement of Ni by Al leads to a change of ground state structure and eventually an increase in magnetocrystalline anisotropy energy~(MAE). We predict for stoichiometric Fe${}_2$NiAl a ground state structure with nearly cubic lattice parameters but alternating layers of Fe and Ni possessing an uniaxial MAE which is even larger than tetragonal L1${}_0$-FeNi. This opens an alternative route for improving the phase stability and magnetic properties in FeNi-based permanent magnets.

arXiv commentarXiv admin note: substantial text overlap with arXiv:2107.08804