The polarization reorientation in ferroelectric nanomaterials under high-strength AC electric fields is intrinsically a frequency-dependent process.However,the related study is not widely seen.We report a phase-field ...The polarization reorientation in ferroelectric nanomaterials under high-strength AC electric fields is intrinsically a frequency-dependent process.However,the related study is not widely seen.We report a phase-field investigation regarding the dynamics of polarization switching and the electromechanical characteristics of a polycrystalline BaTiO_(3) nanofilm under applied frequency from 0.1 to 80 kHz.The grain boundaries and the in-plane strains are considered in the model.The obtained hysteresis and butterfly loops exhibit a remarkable variety of shapes with the changing frequency.The underlying mechanism for the observed frequency-dependent physical properties was discussed via domain structure-based analysis.In addition,we examined the influence of the kinetic coefficient in the Ginzburg-Landau equation as well as the influence of the electric-field amplitude to the frequency dependency.It was found that a higher value of kinetic coefficient or field amplitude tends to enhance the mobility of polarization switching and to transform high-frequency characteristics to low-frequency ones.展开更多
基金This work was supported by the National Natural Science Foundation of China under Grant No.12172046.
文摘The polarization reorientation in ferroelectric nanomaterials under high-strength AC electric fields is intrinsically a frequency-dependent process.However,the related study is not widely seen.We report a phase-field investigation regarding the dynamics of polarization switching and the electromechanical characteristics of a polycrystalline BaTiO_(3) nanofilm under applied frequency from 0.1 to 80 kHz.The grain boundaries and the in-plane strains are considered in the model.The obtained hysteresis and butterfly loops exhibit a remarkable variety of shapes with the changing frequency.The underlying mechanism for the observed frequency-dependent physical properties was discussed via domain structure-based analysis.In addition,we examined the influence of the kinetic coefficient in the Ginzburg-Landau equation as well as the influence of the electric-field amplitude to the frequency dependency.It was found that a higher value of kinetic coefficient or field amplitude tends to enhance the mobility of polarization switching and to transform high-frequency characteristics to low-frequency ones.
