title: Interaction of frustrated magnetic sublattices in ErMnO3.
abstract: A spontaneous or field induced "hidden" phase transition with antiferromagnetic-to-ferromagnetic reordering is disclosed in multiply frustrated hexagonal ErMnO3. It is revealed by Faraday rotation and second harmonic generation as sublattice-sensitive probes to the Er and Mn systems. The acquired phase diagram in the magnetic-field-temperature plane is shown to be a consequence of a broken geometric frustration between the Er and Mn lattices, giving way to anisotropic superexchange between the 3d and 4f ions.
authors.affiliation: Universität Dortmund, Institut für Physik, 44221 Dortmund, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Fiebig
authors.forename: C
authors.initials: C
authors.lastname: Degenhardt
authors.forename: R V
authors.initials: RV
authors.lastname: Pisarev