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Magnetic inversion symmetry breaking and ferroelectricity in TbMnO3

M. Kenzelmann·A. B. Harris·S. Jonas·C. Broholm·J. Schefer·S. B. Kim·C. L. Zhang·S. -W. Cheong·O. P. Vajk·J. W. Lynn
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Abstract

TbMnO3 is an orthorhombic insulator where incommensurate spin order for temperature T_N < 41K is accompanied by ferroelectric order for T < 28K. To understand this, we establish the magnetic structure above and below the ferroelectric transition using neutron diffraction. In the paraelectric phase, the spin structure is incommensurate and longitudinally-modulated. In the ferroelectric phase, however, there is a transverse incommensurate spiral. We show that the spiral breaks spatial inversion symmetry and can account for magnetoelectricity in TbMnO3.

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M. Kenzelmann, A. B. Harris, S. Jonas, C. Broholm, J. Schefer, S. B. Kim, C. L. Zhang, S. -W. Cheong, O. P. Vajk, J. W. Lynn. 2005-06-23. Magnetic inversion symmetry breaking and ferroelectricity in TbMnO3. https://doi.org/10.1103/physrevlett.95.087206

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