First-Principles Calculations of Magnetic Properties of Cr-Doped Ni45Co5Mn37In13 Heusler Alloys

The magnetic and electronic properties of Co- and Cr-doped Ni₅₀Mn₃₇In₁₃ Heusler alloys with a substitution of 5 at.% Co for Ni and 5 at.% Cr for Ni, Mn, or In are investigated in the framework of the density functional theory method. The chemical disorder in the off-stoichiometric Ni-Co-Mn-Cr-In systems was treated in the coherent potential approximation. Three different ferrimagnetic and one ferromagnetic (FM) spin states for austenite and martensite were considered in ab initio calculations. It is found that for both structures, the intersublattice interactions (Mn_Y(Z)-Co, Mn_Y(Z)-Ni, Mn_Y(Z)-Mn_Z(Y), Mn_Y(Z)-Cr, and Cr-Co) provide the largest contribution to the exchange due to the shorter distance compared with the intrasublattice interactions (MnY(Z)-MnY(Z), Co-Co, Ni-Ni, and Cr-Cr). Besides, the MnY-MnZ and MnY(Z)-Cr exchanges in the first shell become five times larger in martensite compared with austenite. The largest anti-FM interaction is observed between MnY(Z)-Cr atoms in martensite.