Elucidating the magnetic structure in a multiferroic system with a bipartite honeycomb network

Recently, a polar magnet Fe2Mo3O8 has garnered significant attention due to its intriguing multiferroic properties. It has a polar space group, and below the magnetic ordering temperature, both the space-inversion and time-reversal symmetries are broken, resulting in a novel magnetoelectric effect. Despite extensive research conducted on this material, the fundamental question about its magnetic configuration remains open. The magnetic Fe ions occupy two distinct oxygen coordination environments, octahedra and tetrahedra, and the question concerning in which site the magnetic moment is larger has not reached a consensus yet. Besides, the effect of Zn doping and its impact on the metamagnetic transition requires further exploration. To shed light on these issues, we plan to conduct single-crystal neutron diffraction on the parent compound Fe2Mo3O8 and a 25% Zn-doped compound Fe1.75Zn0.25Mo3O8.