Non-collinear magnetic ordering in R1/2D1/2MnO3manganites

We discuss the possibility of a non-collinear magnetic structure to be the ground state of the half-doped manganites, as a natural consequence of the recently proposed alternative model to Mn 3+ /Mn 4+ charge ordering in such systems (Phys. Rev. Lett. 89 (2002) 097205). We show that the new non-collinear model and the collinear arrangement known as the CE-state, are almost two degenerate solutions for the refinement of the neutron powder diffraction studies that we have performed on half-doped manganites.