DYNAMICS OF POLARIZATION REVERSAL IN PURIFIED RB2ZNCL4

The dynamics of polarization reversal in sinusoidal fields (0.1Hz less than or equal to f less than or equal to 50kHz) was studied in the fe rroelectric lock-in phase of purified Rb2ZnCl4 crystals. The frequency dependence of remanent polarization and coercive field E-c is qualita tively the same above and below Tapproximate to 160K, where for all m easuring frequencies E-c starts to increase rapidly with decreasing te mperature. A model which treats sideways shifts of planar, nearly regu larly arranged domain walls as the only mechanism of polarization reve rsal in Rb2ZnCl4 is applicable for the quantitative description of fer roelectric hysteresis loops in the whole temperature interval under in vestigation. The anomalous increase of E-c at T seems to be connected to a corresponding increase of the viscosity coefficient.