Unambiguous determination of a structural transition in a polar honeycomb antiferromagnet Fe2Mo3O8

Multiferroicity is an exciting phenomenon applicable in novel devices; when both time-reversal and inversion symmetries are broken, the electric polarisation and the magnetisation can be controlled interchangeably. The practical challenge is finding and understanding materials showing a stronger magnetoelectricity at a higher temperature. In this regard, we focus on the polar magnet Fe2Mo3O8, where a complex poling procedure is unnecessary as the inversion symmetry is already broken. We aim to solve the nuclear structure in the magnetically-ordered phase by using single-crystal neutron diffraction, which will be crucial to understand the magnetoelectric origin.