IMF2017

The dynamical coupling of different order parameters in multiferroic BiFeO₃ (BFO) can result in new effects. In this study, the behavior of polarization under the application of an AC magnetic field superimposed on a DC field (H=H_dc+h_acSin(ωt)) is studied by using an atomistic effective Hamiltonian scheme within a Molecular Dynamics (MD) technique. The dependence of the quadratic magnetoelectric coefficient, β, on the frequency of applied magnetic field is then extracted. It is first found that, when the frequency of applied magnetic field, ω, is within few GHz, the obtained value for β is in the order of 10^-8 C/m²T² which agrees with previously reported measurements. Moreover, the behavior of β significantly changes when the frequency of applied magnetic field becomes close to that of a magnon. Finally, at higher frequencies of applied magnetic field, an additional high frequency oscillation is observed in the behavior of polarization versus time, which is a result of the influence of the natural phonon frequency in addition to the frequency of the applied magnetic field.