title: Symmetry of multiferroicity in a frustrated magnet TbMn2O5.
abstract: Based on measurements of soft-x-ray magnetic scattering and symmetry considerations, we demonstrate that the magnetoelectric effect in TbMn2O5 arises from an internal field determined by S-->q--> x S-->-q--> with S-->q--> being the magnetization at modulation vector q-->, whereas the magnetoelastic 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.
authors.affiliation: National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan.
authors.forename: J
authors.initials: J
authors.lastname: Okamoto
authors.forename: D J
authors.initials: DJ
authors.lastname: Huang
authors.forename: C-Y
authors.initials: CY
authors.lastname: Mou
authors.forename: K S
authors.initials: KS
authors.lastname: Chao
authors.forename: H-J
authors.initials: HJ
authors.lastname: Lin
authors.forename: S
authors.initials: S
authors.lastname: Park
authors.forename: S-W
authors.initials: SW
authors.lastname: Cheong
authors.forename: C T
authors.initials: CT
authors.lastname: Chen