Investigation of the structural competing and atomic ordering in Heusler compounds Fe₂NiSi and Ni₂FeSi under strain condition

Abstract

The structural competing and atomic ordering of the full Heusler compounds Fe 2 NiSi and Ni 2 FeSi under uniform and tetragonal strains have been systematically studied by the first-principles calculation. Both Fe 2 NiSi and Ni 2 FeSi have the XA structure in cubic phase and they show metallic band structures and large magnetic moments (greater than 3 μ B ) at equilibrium condition. Tetragonal distortion can further decrease the total energy, leading to the possible phase transformation. Furthermore, different atom reordering behaviours have been observed: for Fe 2 NiSi, atoms reorder from cubic XA-type to tetragonal L1 0 -type; for Ni 2 FeSi, there is only structural transformation without atom reordering. The total magnetic moments of Fe 2 NiSi and Ni 2 FeSi are mainly contributed by Fe atoms, and Si atom can strongly suppress the moments of Fe atoms when it is present in the nearest neighbours of Fe atoms. With the applied strain, the distance between Fe and Si atoms play an important role for the magnetic moment variation of Fe atom. Moreover, the metallic band nature is maintained for Fe 2 NiSi and Ni 2 FeSi under both uniform and tetragonal strains. This study provides a detailed theoretical analysis about the full Heusler compounds Fe 2 NiSi and Ni 2 FeSi under strain conditions.

Revealing the Potential of Ternary Medium-Entropy Alloys as Exceptional Electrocatalysts toward Nitrogen Reduction: An Example of Heusler Alloys

“…Within the full-Heusler alloy (X 2 YZ) category, two different crystal structures exist, which are known as Cu 2 MnAl-type and Hg 2 CuTi-type, separately. In the Cu 2 MnAl-type structure, all X elements are inside the conventional cell, while the Y element is located on both face centers and corner sites, and the Z element occupies the edge sites.…”

“…The first six alloys were experimentally synthesized as referenced, while the last two were picked from and Ru 2 FeP about their electronic and magnetic properties. 43,44 Within the full-Heusler alloy (X 2 YZ) category, two different crystal structures exist, 45 which are known as Cu 2 MnAl-type and Hg 2 CuTi-type, separately. In the Cu 2 MnAl-type structure, all X elements are inside the conventional cell, while the Y element is located on both face centers and corner sites, and the Z element occupies the edge sites.…”

Highly spin-polarized electronic structure and magnetic properties of Mn2.25Co0.75Al1−xGex Heusler alloys: first-principles calculations

“…It was known that the lattice deformation usually occurs during the lm growth on different substrates. According to the previous theoretical and experimental results, 87 the electronic structure and magnetic properties of Heusler alloys are tunable under the hydrostatic (3 u ) and uniaxial (3 t ) strains. Owing to the varying of the lattice constant, the inter-atomic hybridization interaction and intra-atomic exchange interaction between transitional metal elements will be affected, which will inuence the energy dispersion of the valence and conduction bands in the two spin directions.…”

Elucidation of the Strong Effect of the Annealing and the Magnetic Field on the Magnetic Properties of Ni₂-based Heusler Microwires

“…In order to obtain the necessary structural ordering i.e. L21 and prevent the formation of disordered structures, such as B2, A2, and DO3, which may arise during the alloy manufacturing process, the half and full metallic Heusler alloys prepared by physical vapor deposition, i.e., thin films forms, ball milling, or by arc melting, are crucial [14,15]. To avoid the formation of unneeded phase structures, lengthy annealing times at high temperatures are used.…”