A possible coupling mechanism between magnetism and dielectric properties in EuTiO 3 within the framework of the transverse-field Ising model

Abstract

The dielectric constant of the quantum paraelectric EuTiO 3 exhibits a sharp decrease at about 5.5 K, at which temperature antiferromagnetic ordering of the Eu spins simultaneously appears, indicating coupling between the magnetism and dielectric properties. The transverse-field Ising model and Heisenberg model are successfully applied to EuTiO 3 electrical and magnetic subsystems, respectively. By adding an appropriate coupling term between the magnetic and electrical subsystems, which is related to the interaction of the Heisenberg spin and pseudospin, we investigate intrinsic coupling between the magnetic and electrical subsystems and successfully obtain its special dielectric constant, which is in good agreement with the experimental data.