Magnetic structure of the field-induced multiferroic GdFe3(BO3)4

We report a magnetic x-ray scattering study of the field-induced multiferroic GdFe3(BO3)(4). Resonant x-ray magnetic scattering at the Gd L-II,L-III edges indicates that the Gd moments order at T-N approximate to 37 K. The magnetic structure is incommensurate below T-N, with the incommensurability decreasing monotonically with decreasing temperature until a transition to a commensurate magnetic phase is observed at T approximate to 10 K. Both the Gd and Fe moments undergo a spin reorientation transition at T-SR approximate to 9 K such that the moments are oriented along the crystallographic c axis at low temperatures. With magnetic field applied along the a axis, our measurements suggest that the field-induced polarization phase has a commensurate magnetic structure with Gd moments rotated similar to 45 degrees toward the basal plane, which is similar to the magnetic structure of the Gd subsystem observed in zero field between 9 and 10 K, and the Fe subsystem has a ferromagnetic component in the basal plane.