in the magnetic-field-induced canted AFM state.*

BiFeO₃ is a well-known room temperature multiferroic material where the cycloidal magnetic order induces electric polarization in addition to existing polarization. The cycloidal order is transformed by strong magnetic fields into a canted antiferromagnetic (AFM) order above B=18T and the cycloidal modes are replaced by excitations of the canted AFM structure [U. Nagel et al., Phys. Rev. Lett., 110:257201, (2013)].
Here we present the THz spectroscopy results for three different magnetic field orientation, parallel to hexagonal c axis, perpendicular and parallel to a axis, measured on the single FE domain crystals grown by the laser-diode heating floating-zone method [T. Ito et al., Cryst. Growth Des. 11 (2011) 5139]. The dependence of mode frequencies as a function of magnetic field were studied up to 35T at liquid He temperatures. In light of these experimental results, a microscopic model is proposed for the canted AF phase.