Magnetic structure and spin correlations in magnetoelectric honeycomb Mn4Ta2O9

The coupling between magnetic ordering and electric polarization in magnetoelectrics is technically relevant and not yet completely understood. The elucidation of this requires a comprehension of underlying magnetic interactions and the electronic structure. Here, the authors investigate the magnetoelectric honeycomb compound Mn${}_{4}$Ta${}_{2}$O${}_{9}$, by means of neutron scattering and electronic structure calculations, to reveal the ingredients that determine the ground state. For this compound, the ground state is determined by an electron correlation assisted magnetic dipole-dipole interaction. The investigation here offers detailed insight into the factors that determine the ground-state manifold and the role of electron correlation on the strength of anisotropy.