“…In a previous experimental paper, 15 some authors of this paper proposed that the helical magnetic structure structure in RFMO, the origin of which remained unclear, is in fact induced by the structural axiality through symmetric exchange. We also show that the axial distorarXiv:1403.1413v1 [cond-mat.mtrl-sci] 6 Mar 2014 tion can give rise to a second component of the electrical polarization, so that the total polarization can be written phenomenologically as P c = c 1 σ t + c 2 Aσ h , where c 1 and c 2 are constants, σ t represents the in plane triangular chirality, σ h is the magnetic helicity along the c direction, and A is the component of the axial rotation parallel to the electric polarization (in RFMO, the ferroaxial vector is A = (0, 0, A), hence A is the magnitude of the ferroaxial distortion whose sign is determined by the structural rotation direction).…”