Electronic structure and magnetism of Mn2CuAl: A first-principles study

Abstract

Abstract The electronic structure and magnetism of a new Mn-based Heusler alloys Mn2CuAl has been studied by first-principles calculations. The calculations suggest that Mn2CuAl crystallizes in the Hg2CuTi type of structure, in which the Cu atoms have Al as nearest neighbors. As a consequence, the Mn atoms occupy two nearest neighbor sublattices A and B. Like the well known Heusler alloy Cu2MnAl, the magnetic moment of Mn2CuAl also comes from the two Mn atoms in the lattice, while the Cu atom is almost nonmagnetic. At equilibrium lattice constant, Mn2CuAl is a ferrimagnet with moment of 0.22μB. The partial spin moments of Mn (A) and Mn (B) are −3.52μB and 3.74μB, respectively. The small total moment comes from the antiparallel configurations of the Mn partial moments. With a small contraction of the lattice, the total moment becomes near zero and a half-metallic antiferromagnetic state is observed.