Magnetic Structures of Mn2As and Mn2Sb0.7As0.3

Abstract

Neutron diffraction has been performed on powder specimens of Mn2As and Mn2Sb0.7As0.3. Mn2As has the antiferromagnetic structure found in Mn1.9Cr0.1Sb below the exchange inversion temperature. The atomic moments are 3.7 and 3.5 Bohr magnetons for Mn(I) and Mn(II), respectively. The moments lie perpendicular to the tetragonal axis. The magnetic structure of Mn2Sb0.7As0.3, which undergoes exchange inversion over the 35° to 115°C temperature range, is the same as that of Mn2As at room temperature and is the same as that of ferrimagnetic Mn2Sb at 150°C. The atomic moments at room temperature (antiferromagnetic) are 2.3 and 2.8 Bohr magnetons, respectively, for Mn(I) and Mn(II). The moments are perpendicular to the tetragonal axis at room temperature and parallel to it at 150°C.