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arXiv · 1710.10676

Magnetic field control of cycloidal domains and electric polarization in multiferroic BiFeO$_3$

S. Bordács·D. G. Farkas·J. S. White·R. Cubitt·L. DeBeer-Schmitt·T. Ito·I. Kézsmárki
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Abstract

The magnetic field induced rearrangement of the cycloidal spin structure in ferroelectric mono-domain single crystals of the room-temperature multiferroic BiFeO$_3$ is studied using small-angle neutron scattering (SANS). The cycloid propagation vectors are observed to rotate when magnetic fields applied perpendicular to the rhombohedral (polar) axis exceed a pinning threshold value of $\sim$5\,T. In light of these experimental results, a phenomenological model is proposed that captures the rearrangement of the cycloidal domains, and we revisit the microscopic origin of the magnetoelectric effect. A new coupling between the magnetic anisotropy and the polarization is proposed that explains the recently discovered magnetoelectric polarization to the rhombohedral axis.

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S. Bordács, D. G. Farkas, J. S. White, R. Cubitt, L. DeBeer-Schmitt, T. Ito, I. Kézsmárki. 2017-10-29. Magnetic field control of cycloidal domains and electric polarization in multiferroic BiFeO$_3$. https://doi.org/10.1103/physrevlett.120.147203

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