Dielectric Dispersion of KH2PO4Powder in the Ferroelectric Phase

Complex dielectric constant of the KH 2 PO 4 powder with the particle size of 25–53 µm has been measured between 20 Hz and 1 MHz. At 1 kHz three peaks of ε '' denoted as ζ, η and ξ were found, respectively, at 105 K, 55 K and 12 K in the ferroelectric phase from 4.2 K to the Curie temperature. The origin of the peak ζ is ascribed to the relaxation of anchored domain wall motion, and η to the freezing process of domain wall motion. A possible origin of the peak ξ is the reorientation of dipoles in the domain walls.