Direct transition from a disordered to a multiferroic phase on a triangular lattice.
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.
Kenzelmann
M
M
Laboratory for Solid State Physics, ETH Zurich, CH-8093 Zurich, Switzerland.
Lawes
G
G
Harris
A B
AB
Gasparovic
G
G
Broholm
C
C
Ramirez
A P
AP
Jorge
G A
GA
Jaime
M
M
Park
S
S
Huang
Q
Q
Shapiro
A Ya
AY
Demianets
L A
LA