Peculiarities of nanotwin structures in Ni2Mn1,5In0,5 and Ni2Mn1,75In0,25 Heusler alloys

This article presents the results of calculating the phase stability and structural properties of the twin structures of Ni2Mn1,5In0,5 and Ni2Mn1,75In0,25 Heusler alloys. The structures with a random and periodic arrangement of Mn-excess atoms in the In sublattice were considered. It is shown that the compositions of Ni2Mn1,5In0,5 and Ni2Mn1,75In0,25, with modulation periods of 2-5 and 3-3, respectively, are stable relative to all twin structures. The distribution of Mn-excess atoms does not affect the structural characteristics of the systems. The nanotwin structures of Ni2Mn1,5In0,5 and Ni2Mn1,75In0,25 alloys possess similar crystal lattice parameters. An increase in the stability of the structures with respect to the decomposition into constituent stable components is observed with an increase in the concentration of Mn.