Effect of Co doping on martensitic transformation and magnetic properties of Ni50Mn35.4In14.6 alloy by first-principles calculations

The effects of Co doping on the phase stability, martensite transformation and magnetic properties of Ni24-xMn17In7Cox (x= 0-5) ferromagnetic shape memory alloy were systematically investigated by the first-principles calculations. Co atom prefers to occupy the Ni sublattice. Co doping increases equilibrium lattice constant of austenite and decreases phase stability of austenite, 6 M and NM martensites. When 0 <= x < 2, the martensite transformation during cooling is PA -> FA -> 6 M -> NM; whilst x >= 2, the corresponding martensite transformation is PA -> FA -> NM. The martensitic transformation from austenite to martensite (6 M and NM) accompanies the ferromagnetic to ferrimagnetic transition in the Co content 0 <= x <= 2. However, the ferromagnetic state is popular in the whole martensitic transformation process for x > 2. The origin of magnetic properties and magnetostructure transformation were discussed based on electronic density of states. (C) 2019 Elsevier B.V. All rights reserved.