Symmetry of Multiferroicity in a Frustrated MagnetTbMn2O5

• DOI: 10.1103/physrevlett.98.157202
• Publication Date: 2007-04-10T21:06:40Z
• Authors: J. Okamoto; D. J. Huang; C.-Y. Mou; K. S. Chao; H.-J. Lin; S. Park; S-W. Cheong; C. T. Chen
• Keywords: Condensed Matter - Strongly Correlated Electrons; Condensed Matter - Materials Science; Strongly Correlated Electrons (cond-mat.str-el); 0103 physical sciences; Materials Science (cond-mat.mtrl-sci); FOS: Physical sciences; 01 natural sciences

Based on measurements of soft x-ray magnetic scattering and symmetry considerations, we demonstrate that the magnetoelectric effect in TbMn$_2$O$_5$ arises from an internal field determined by $\vec{S}_{\vec{q}} \times {\vec{S}_{-\vec{q}}}$ with $\vec{S}_{\vec{q}}$ being the magnetization at modulation vector $\vec{q}$, whereas the magneto-elastic effect in the exchange energy governs the response to external electric fields. Our results set fundamental symmetry constraints on the microscopic mechanism of multiferroicity in frustrated magnets.