Ferroelectric dynamic of some H-bonded crystals

Abstract The results of study on dynamic dielectric properties of some H-bonded crystals are presented. It is shown that relaxational soft modes are responsible for the ferroelectric phase transition in RbD2PO4, PbHPO4 and NH4HSeO4 and their contribution accounts for the static permittivity. Glass-like dielectric relaxation with temperature depended relaxation time τ was observed in the ferroelastic phase of Cs5D3(SO4)4. Non-Debye dielectric relaxations characteristic to ionic conductors were observed in the high-temperature phases of Cs5D3(SO4)4 and NH4HSeO4.