Isotropic Magnetoelectric Effect in Multiferroic Material Studied by Resonant X-ray Scattering

Abstract

Isotropic ME effect was observed in multiferroic Tb_1-xGd_xMn₂O₅, where electric polarization reappears along the b axis as a response to application of a magnetic field along each crystallographic axis. This isotropic ME effect is distinct from those observed in other RMn₂O₅ and multiferroic materials. Employing resonant X-ray scattering, we revealed that the isotropic ME effect is attributed to competition between two different magnetic ordering. In addition, measurement of oxygen spin polarization under magnetic field suggests that charge transfer between Mn and O ions have microscopic contribution to the ME effect.