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Ferroelectricity induced by acentric spin-density waves in YMn$_2$O$_5$

L. C. Chapon·P. G. Radaelli·G. R. Blake·S. Park·S-W. Cheong
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Abstract

The commensurate and incommensurate magnetic structures of the magnetoelectric system YMn$_{2}$O$_{5}$, as determined from neutron diffraction, were found to be spin-density waves lacking a global center of symmetry. We propose a model, based on a simple magneto-elastic coupling to the lattice, which enables us to predict the polarization based entirely on the observed magnetic structure. Our data accurately reproduce the temperature-dependence of the spontaneous polarization, in particular its sign reversal at the commensurate-incommensurate transition.

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L. C. Chapon, P. G. Radaelli, G. R. Blake, S. Park, S-W. Cheong. 2005-11-07. Ferroelectricity induced by acentric spin-density waves in YMn$_2$O$_5$. https://doi.org/10.1103/physrevlett.96.097601

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