Neutron powder diffraction experiments reveal that Co4Nb2O9 forms a noncollinear in-plane magnetic structure with Co2+ moments lying in the ab plane. The spin-wave excitations of this magnet were measured by using inelastic neutron scattering and soundly simulated by a dynamic model involving nearest and next-nearest neighbour exchange interactions, in-plane anisotropy and the Dzyaloshinskii-Moriya interaction. The in-plane magnetic structure of Co4Nb2O9 is attributed to the large in-plane anisotropy while the noncollinearity of the spin configuration is attributed to the Dzyaloshinskii-Moriya interaction. The high magnetoelectric coupling effect of Co4Nb2O9 in fields can be explained by its special in-plane magnetic structure.
@article{arxiv.1705.04017,
title = {Spin Dynamics and Magnetoelectric Coupling Mechanism of Co4Nb2O9},
author = {Guochu Deng and Yiming Cao and Wei Ren and Shixun Cao and Andrew J. Studer and Nicolas Gauthier and Michel Kenzelmann and Gene Davidson and Kirrily C. Rule and Jason S. Gardner and Paolo Imperia and Clemens Ulrich and Garry J. McIntyre},
journal= {arXiv preprint arXiv:1705.04017},
year = {2018}
}