Debye-like relaxation behavior and electric field induced dipole re-orientation of the 0.6BaTiO3-0.4Bi(Mg1/2Ti1/2)O3 ceramic

Abstract Mechanisms of the dielectric relaxation and electric field induced dipole re-orientation process in the 0.6BaTiO 3 -0.4Bi(Mg 1/2 Ti 1/2 )O 3 ceramic have been investigated by a combination of experiments and simulations. Using the modified Debye relaxation theory, the observed strong relaxation is related to the evolution of the distribution of relaxation times with increasing temperatures. The increased freezing temperature under dc bias electric fields indicates that the nonlinear dielectric behavior has positive contributions to the total polarization. In relaxor state, the dielectric response of the 0.6BaTiO 3 -0.4Bi(Mg 1/2 Ti 1/2 )O 3 ceramic shows a maximum value with the increasing external fields, which is attributed to two main polarization mechanisms, lattice phonon polarization and re-orientation of polar clusters. The contribution of these two polarization mechanisms is separated by the multi-polarization model, indicating that the re-orientation of polar clusters is responsible for the increase of the dielectric constant. At last, Monte Carlo method is performed to simulate the dipole re-orientation process, and the simulated results are consistent with experimental findings. This study provides a different perspective to investigate the relaxor materials with isolated polar clusters.