The magnetic structure of DyFeO 3 revisited: Fe spin reorientation and Dy incommensurate magnetic order.

High resolution and high intensity neutron powder diffraction is used to study the ground state magnetic order and the spin reorientation transition in the orthoferrite DyFeO 3 . The transition from the high temperature k = 0 Γ 4 ( G x A y F z ) to the low temperature Γ 1 ( A x G y C z ) type order of the Fe-sublattice is found at T SR = 73 K and does not show any thermal hysteresis. Below T N2 = 4 K the Dy-sublattice orders in an incommensurate magnetic structure with k = [0, 0, 0.028] while the Fe-sublattice keeps its commensurate Γ 1 type order. DyFeO 3 is the first orthoferrite R FeO 3 to possess an incommensurate magnetic order of the rare earth sublattice under zero field conditions; an important piece of information neglected in the recent discussion of its multiferroic properties.