Two relaxation processes in the inhomogeneous deuterated ferroelectric Rb 0.96 (ND 4 ) 0.04 D 2 AsO 4

This paper reports the results of the influence of dc electric field on the complex permittivity ε * = ε ′ – iε ″ in the inhomogeneous deuterated ferroelectric Rb 1− x (ND 4 ) x D 2 AsO 4 , where x = 0.04 (DRADA with x = 0.04). In this crystal the coexistence of ferroelectric and short‐range ordered (glass) phases takes place at a low temperature below T c . At T c = 155 K the transition to the ferroelectric state is reported. Two relaxation processes were observed in the perpendicular orientation to the ferroelectric c ‐axis in the temperature range from 3.5 K to 300 K. The influence of a dc electric field on the temperature dependence of the dielectric losses shows clearly two different relaxation processes. At temperatures around 60 K, there is a dispersion related to the embryos of the glass clusters, which coexists with ferroelectric domains. The dispersion around 120 K due to frozen domain wall motion is also observed in the perpendicular direction to the ferroelectric c ‐axis along hydrogen bonds. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)