Direct transition from a disordered to a multiferroic phase on a triangular lattice
American Physical Society
We report the first direct transition from a paramagnetic and paraelectric phase to an incommensurate multiferroic in the triangular lattice antiferromagnet RbFe(MoO4)2. Ferroelectricity is observed only when the magnetic structure has chirality and breaks inversion symmetry. A Landau expansion of symmetry-allowed terms in the free energy demonstrates that chiral magnetic order can give rise to a pseudoelectric field, whose temperature dependence agrees with experiment.
triangular lattice, direct transition, chirality, broken inversion symmetry, chiral magnetic order, pseudoelectric field, rubidium compounds, paramagnetic materials, magnetc transitions, ferroelectric transitions, dielectric materials, multiferroics, magnetic transitions, iron compounds, free energy, Landau expansion, ferroelectricity, RbFe(MoO4)2
Physical Review Letters 29 June 2007, vol.98, no.26, pp. 267205/1-4