Huge spin-driven polarizations at room temperature in bulk BiFeO$_{3}$
ORAL
Abstract
Although BiFeO$_{3}$ is one of the most investigated multiferroics, its magnetoelectricity and spin-driven polarizations are barely understood on an atomistic level. By combining a first-principles approach with a spin-cycloid model, we report hidden but huge spin-driven polarizations at room temperature in bulk BiFeO$_{3}$. One of the polarizations reaches $\sim$ 0.03 C/m$^{2}$, which is larger than any other spin-driven polarization in a bulk material by one order of magnitude. By comparing our results with intrinsic measurements such as neutron scattering, Raman spectroscopy, IR directional dichroism, and high magnetic-field measurements, we disentangle all the hidden spin-driven polarizations due to exchange-striction, spin-current, and single-ion-anisotropy. We find that the broken inversion symmetries of the $R$3c structure of BiFeO$_{3}$ induce the strong response of the magnetic couplings to an electric field and are responsible for the associated huge spin-driven polarizations.
*This research is sponsored by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division and by the Scientific User Facilities Division, Office of Basic Energy Sciences, US Department of Energy.
–