Origin of multiferroism in the charge frustrated LuFe2O4 compound

Abstract We propose a microscopic model in order to study the multiferroic properties of LuFe 2 O 4 . It is shown that the real part of the dielectric constant ϵ has a plateau near the magnetic phase transition T N = 240 K . At room temperature ϵ decreases strongly by applying an external magnetic field H . This behavior is an evidence for a strong coupling of spins and electric dipoles in agreement with the experimental data. The observed kinks in the temperature dependence of the phonon energy and damping for the E g 3 mode around the ferroelectric and ferrimagnetic transition temperatures show that this phonon mode is closely related to the structural, magnetic and ferroelectric properties of LuFe 2 O 4 .