First-principles calculations of magnetic properties of Cr-doped Ni45Co5Mn37In13 Heusler alloys

In this work we have studied the effect of Cr addition on magnetic properties in the Ni₄₅Co₅Mn₃₇In₁₃ alloy, in which the giant inverse MCE has been recently observed by Liu et al. In order to calculate the magnetic exchange parameters J_ij, magnetic moments and electronic density of states (DOS) curves we have used the Spin-Polarized Relativistic Korringa-Kohn-Rostoker (SPR-KKR) package with the generalized gradient approximation for the exchange correlation functional in the formulation of Perdew, Burke and Ernzerhof (PBE) . The chemical disorder in the off-stoichiometric Ni-Co-Mn-Cr-In systems was treated in the coherent potential approximation (CPA) . Calculations have been carried out for four magnetic configurations referred to as the ferromagnetic (FM) state (all spins of Ni, Co, Cr, Mn_Y, and Mn_Z atoms are parallel) and three ferrimagnetic states: FIM-I (spin of Cr on either X, Y or Z lattice is reversed), FIM-II (spins of Mn_Z are reversed), and FIM-III (spins of Mn_Z and Cr are reversed) . Here, Mn_Y and Mn_Z refer to Mn located on the original Mn sites and on the Z (In) sites, respectively . In order to calculate the variation of the total energy (at T = 0 K) with tetragonal distortion of different spin configurations, we considered that the volume V₀ = a₀³ ≈ a²c does not change with tetragonal distortions .