Neutron Diffraction Studies of Mn-Zn Alloys

Neutron diffraction measurements were made on Mn-Zn alloys in order to investigate the magnetic structures and the atomic superlattice structures. The following superlattices were confirmed: α'-MnZn 3 is of the Cu 3 Au type, ε '-MnZn 3 of the Ni 3 Sn type, and β 1 -MnZn of the CsCl type. Crystallographic and magnetic structures of β-Mn 3 Zn 2 are similar to thoes of β 1 -MnZn. Both ε '-MnZn 3 and β 1 -MnZn exhibit a spontaneous magnetization at room temperature. It seems that the former is simply ferromagnetic while the latter has an angular arrangement of the magnetic moments. An antiferromagnetic structure of α'-MnZn 3 at low temperatures is associated with a tetragonal distortion of the lattice, in which the magnetic moments in a c -plane are parallel to each other and antiparallel to those in adjacent c -planes.