Resonance and Relaxational Dispersions around the Domain Freezing Temperature in KH₂PO₄

Abstract

The resonance and the relaxational dielectric dispersions of KH₂PO₄ found in the ferroelectric phase were examined for ordinary and lossy specimens. The magnitudes of these two dispersions decreased markedly with crystal defects as well as with a d.c. bias field. A universal relation between the free dielectric constant ε^X and the elastic stiffness C₆₆^E was found regardless of the specimens and their states examined. The small C₆₆^E and the large ε^X were obtained for the specimens with high densities of domain walls. The mean value and the standard deviation of the energy parameter E in the relaxation time, τ=τ₀ exp {E⁄(T−T₀)}, as well as the Vogel-Fulcher temperature T₀ decreased with the crystal defects. A possible model for the domain freezing is proposed in connection with these two dispersions.