Session H12: Lattice and Magnetic Properties of Multiferroics
8:00 AM–11:00 AM, Tuesday, March 11, 2008
Morial Convention Center Room: 203
Sponsoring Unit:
DCMP
Chair: Andrei Sushkov, University of Maryland
Abstract ID: BAPS.2008.MAR.H12.13
Abstract: H12.00013 : Magnetically-induced ferroelectric polarization in a molecule-based quantum magnet
10:24 AM–10:36 AM
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Abstract 
Authors:
Vivien Zapf
Frederik Fabris
(National High Magnetic Field Lab, Los Alamos National Lab)
Michel Kenzelmann
(Laboratory for Solid State Physics, ETH H\"onggerberg, Zurich)
Fedor Balakirev
(NHMFL-LANL)
Ying Chen
Colin Broholm
(Dept of Physics and Astronomy, Johns Hopkins University)
Ferroelectricity coupled to antiferromagnetic (AFM) order has been observed in the organic S=1/2 chain compound CDC (CuCl$_{2}$ 2(CH$_{3})_{2}$SO). For magnetic fields along the orthorhombic c-axis, AFM order occurs below T$_{N}$ = 0.93 K and H $\sim $ 4 T. A spin-flop transition above H$_{sf}$ = 0.35 T leads to a magnetically ordered state that breaks inversion symmetry along the b-axis for 0.35 T $<$ H $<$ 4 T. Measurements of the pyroelectric effect and the dielectric constant along b indicate ferroelectricity occurring in this same region of HT phase space with the spin polarization closely tracking the magnetic order parameter. The ferroelectric polarization is observed without electrically poling the material, and polarization switching can be observed by consecutive field sweeps in the same direction. While the magnetically-induced ferroelectricity in CDC is far from practical temperatures and fields, it nevertheless demonstrates that this phenomena can occur in a whole new class of compounds.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2008.MAR.H12.13