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arXiv · 1110.4585

Giant improper ferroelectricity in the ferroaxial magnet CaMn7O12

R. D. Johnson·L. C. Chapon·D. D. Khalyavin·P. Manuel·P. G. Radaelli·C. Martin
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Abstract

In rhombohedral CaMn7O12, an improper ferroelectric polarization of magnitude 2870 μC m-2 is induced by an incommensurate helical magnetic structure that evolves below TN1 = 90 K. The electric polarization was found to be constrained to the high symmetry three-fold rotation axis of the crystal structure, perpendicular to the in-plane rotation of the magnetic moments. The multiferroicity is explained by the ferroaxial coupling mechanism, which in CaMn7O12 gives rise to the largest magnetically induced, electric polarization measured to date.

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R. D. Johnson, L. C. Chapon, D. D. Khalyavin, P. Manuel, P. G. Radaelli, C. Martin. 2011-10-20. Giant improper ferroelectricity in the ferroaxial magnet CaMn7O12. https://doi.org/10.1103/physrevlett.108.067201

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