Abstract
The magnetic structure of multiferroic GdMn2O5 is studied by x-ray magnetic scattering, both off resonance and in resonant conditions at the Gd L-III edge. Temperature dependence of magnetic Bragg reflections shows an initial incommensurate (ICM) ordering appearing at T similar to 40K with magnetic propagation vector k(ICM) similar to(0.49 0 0.18) which condenses at T similar to 33K in a commensurate (CM) wave vector k(CM)=(1/2 0 0). In the CM phase Gd3+ ions appear to order spontaneously at the same temperature as Mn ions. Azimuthal scans allowed for the precise determination, from x-ray magnetic scattering only, of the orientation and magnitude of the Gd3+ magnetic moments. The Gd3+ magnetic isotropy allows for the Gd ions to mimic the Mn4+ magnetic sublattice via Gd-Mn-Gd superexchange interactions