title: Symmetry conditions for type II multiferroicity in commensurate magnetic structures.
abstract: Type II multiferroics are magnetically ordered phases that exhibit ferroelectricity as a magnetic induced effect. We show that in single-k magnetic phases the presence in the paramagnetic phase of non-symmorphic symmetry combined with some specific type of magnetic propagation vector can be sufficient for the occurrence of this type of multiferroic behaviour. Other symmetry scenarios especially favourable for spin driven multiferroicity are also presented. We review and classify known type II multiferroics under this viewpoint. In addition, some other magnetic phases which due to their symmetry properties can exhibit type II multiferroicity are pointed out.
authors.affiliation: Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Tecnología, Universidad del País Vasco (UPV/EHU), Apartado 644, 48080 Bilbao, Spain.
authors.forename: J M
authors.initials: JM
authors.lastname: Perez-Mato
authors.forename: S V
authors.initials: SV
authors.lastname: Gallego
authors.forename: L
authors.initials: L
authors.lastname: Elcoro
authors.forename: E
authors.initials: E
authors.lastname: Tasci
authors.forename: M I
authors.initials: MI
authors.lastname: Aroyo