Magnetic structures of Y6(Fe1−xMnx)23 compounds

Abstract

Neutron diffraction studies of eleven compounds across the compositional range of the Y₆(Fe_1−xMn_x)₂₃ system reveal the presence of substantial preferential atomic ordering of Fe and Mn atoms on the four transition metal crystallographic sites. Throughout the entire compositional range, Mn atoms prefer to occupy the f₂ site and Fe atoms the f₁ site. Neutron diffraction profile refinements show no long range magnetic ordering occurring in the compositional range from x = 0.4 to 0.75 as a consequence of the sharply reduced exchange interactions in the ternary compounds. The average Fe moments on each of the sites are reduced in the Fe‐rich ternaries. The manganese atoms are nonmagnetic. In the Mn‐rich ternaries the Fe atoms have no spontaneous moments and the Mn moments are decreased dramatically from Y₆Mn₂₃.