Local atomic configuration approach to the nonmonotonic concentration dependence of magnetic properties of Ni₂Mn_1+xZ_1-x (Z = In, Sn, Sb) Heusler alloys

The Ni(2)Mn(1+x)Z(1-x) Heusler alloys, where Z = In, Sn, Sb are attractive candidates for shape memory applications. The effect is directly related to their magnetic properties. We have studied these systems by ab-initio calculations and experiments, focusing on magnetic moments and exchange-bias fields. The calculations indicate that the composition dependence of the total magnetic moment is due to competing ferro-magnetic and antiferromagnetic alignment between Mn atoms on different sublattices and with different local environments. This phenomenon can also explain the composition dependence of the exchange-bias effect. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.