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

• Main Authors: Sokolovskiy, Vladimir V, Miroshkina, Olga N, Buchelnikov, Vasiliy D, Gruner, Markus E
• Format: Journal Article
• Language: English
• Published: 24-09-2021
• Subjects: Physics - Materials Science
• DOI: 10.48550/arxiv.2109.12005

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.