The magnetic structures of YMnO 3-? and HoMnO 3

The Mn spin structures of the hexagonal RMnO3 structures form homometric, i.e. indistinguishable, pairs in neutron diffraction if then site parameter x of Mn in (x,0,0) is exactly 1/3. We solve the problem for HoMnO3 and YMnO3-δ neutron-diffraction data when x deviates slightly from 1/3. In HoMnO3 the Ho spins are long-range-ordered below 32.5 K and the Mn/Ho spin structure shows a re-orientational transition at ∼6 K, which implies a 16% increase of the Mn sublattice magnetization.