Magnetoelectric coupling in ferroelectromagnets with antiferroelectric and antiferromagnetic orders

This paper reports a theoretical prediction of magnetoelectric-coupling-induced ferromagnetic ordering behavior in ferroelectromagnets with antiferroelectrically and antiferromagnetically ordered components. A Monte-Carlo algorithm based on Janssen model with an intrinsic magnetoelectric coupling between electric polarization and Ising spin is developed. A mean-field approach based on the Heisenberg model is proposed. The simulation reveals that both weak ferromagnetic order and weak ferroelectric order below certain temperature can be activated by the magnetoelectric coupling and by applying external electrical field. The mean-field approach confirms the weak-ferromagnetic phase transitions revealed by the simulation.