Dynamics of polarization reversal in purified Rb 2 ZnCl 4

Abstract

The dynamics of polarization reversal in sinusoidal fields (0. 1Hz≤f≤50kHz) was studied in the ferroelectric lock-in phase of purified Rb₂ZnCl₄ crystals. The frequency dependence of remanent polarization and coercive field E_c is qualitatively the same above and below T*≈160K, where for all measuring frequencies E_c starts to increase rapidly with decreasing temperature. A model which treats sideways shifts of planar, nearly regularly arranged domain walls as the only mechanism of polarization reversal in Rb₂ZnCl₄ is applicable for the quantitative description of ferroelectric hysteresis loops in the whole temperature interval under investigation. The anomalous increase of E_c at T* seems to be connected to a corresponding increase of the viscosity coefficient.