Features of the Influence of Atomic Ordering on the Structural and Magnetic Properties of the Heusler Alloy Ni2Mn1.5Sn0.5

Abstract

The effect of atomic ordering on the structural and magnetic properties of the crystal structures of the austenite and martensite phases of the Heusler alloy Ni₂Mn_1.5Sn_0.5 has been studied within the density functional theory (DFT). The cubic L2₁, tetragonal L1₀, and orthorhombic 4O structures are considered. The L2₁ phase demonstrates a lower stability in view of its higher energy with respect to the L1₀ and 4O phases. The presence of the antiferromagnetic plane containing Mn atoms in the computational box of L1₀ makes it less favorable by 10 meV/atom in comparison with the 4O phase. However, dilution of the antiferromagnetic plane with Sn atoms leads to increasing stability of the L1₀ structure. An energetically favorable atomic configuration was predicted, at which the L1₀ structure becomes more favorable by 21 meV/atom than the 4O structure. The obtained results qualitatively describe the existing experimental data.