Thermodynamic and dynamic dielectric properties of one-dimensional hydrogen bonded ferroelectric of PbHPO4-type

Within the modified model of proton ordering of one-dimensional ferroelectric having hydrogen bonds of PbHPO4-type, their thermodynamic and dynamic characteristics are studied and calculated taking into account the linear (by crystal deformations ϵi (i=1,3) and ϵ4) contributions into the energy of a proton system but without taking into account the tunneling in the two-particle cluster approximation. There has been obtained a good quantitative description of the temperature dependence of polarization, static dielectric permittivity, heat capacity and frequency dependence of dynamic dielectric permittivity at different temperatures for PbHPO4 and PbHDO4 crystals.