Investigating Magnetism in the Multiferroic RA$_{\mathrm{3}}$(BO$_{\mathrm{3}})_{\mathrm{4}}$ System at Low Temperature

The Multiferroic system HoAl$_{\mathrm{3}}$BO$_{\mathrm{3}})_{\mathrm{4}}$ is known to exhibit a strong coupling of magnetic field to the electrical polarization at low temperature. The nature of magnetic order and Ho site at low temperature is not known. However measurements reveal magnetic ordering in Ho site in HoFe$_{\mathrm{3}}$(BO$_{\mathrm{3}})_{\mathrm{4}}$ at low temperature. Our previous work revealed enhanced correlation between neighboring HoO$_{\mathrm{6}}$ polyhedra for magnetic fields up to 3 T. In this work, we further investigate the origin of the magnetoelectric effect of the RA$_{\mathrm{3}}$(BO$_{\mathrm{3}})_{\mathrm{4}}$ system by neutron scattering and structural optimization with DFT calculation. This work is supported by DOE Grant DE-FG02-07ER46402.