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.
Laboratory for Solid State Physics, ETH Zurich, CH-8093 Zurich, Switzerland.
M
M
Kenzelmann
G
G
Lawes
A B
AB
Harris
G
G
Gasparovic
C
C
Broholm
A P
AP
Ramirez
G A
GA
Jorge
M
M
Jaime
S
S
Park
Q
Q
Huang
A Ya
AY
Shapiro
L A
LA
Demianets