Theoretical study of mutual control mechanism between magnetization and polarization in multiferroic materials

Abstract

The mutual control mechanism between magnetization and polarization in multiferroic materials is studied. The system contains a ferromagnetic sublattice and a ferroelectric sublattice. To describe the magneto-electric coupling, we propose a linear coupling Hamiltonian between ferromagnetism and ferroelectricity without microscopic derivation. This coupling enables one to retrieve the hysteresis loops measured experimentally. The thermodynamic properties of the system are calculated, such as the temperature dependences of the magnetization, polarization, internal energy and free energy. The ferromagnetic and ferroelectric hysteresis loops driven by either a magnetic or an electric field are calculated, and the magnetic spin and pseudo-spin are always flipped synchronously under the external magnetic and electric field. Our theoretical results are in agreement with the experiments.

Magnetoelectric coupling and spin reorientation in BiFeO3

“…There has been increasing recent interest in ME multiferroics , which are materials that show spontaneous magnetic and electric ordering in the same phase. In many papers, the electric properties in multiferroic EuTiO 3 , type‐I multiferroics , BFO , hexagonal h‐ R MnO 3 compounds , R Mn 2 O 5 , and composite multiferroic thin films are studied using the Transverse Ising model (TIM) with S = 1/2. This is reasonable, for example, in the case of h‐ R MnO 3 and R Mn 2 O 5 .…”