Influence of uniaxial and hydrostatic pressures and a longitudinal electric field on the thermodynamic characteristics of the quasi-one-dimensional ferroelectric CsH2PO4

We propose a two-sublattice proton ordering model for the quasi-one-dimensional CsH 2 PO 4 ferroelectric with hydrogen bonds, which takes into account contributions to the energy of the proton subsystem that are linear in the lattice strains ε 1 , ε 2 , ε 3 , and ε 5 . The model also takes into account the dependence of the e(cid:27)ective dipole moments of pseudospins on the order parameters, which enables us to coordinate the values of the e(cid:27)ective dipole moments in the paraelectric and ferroelectric phases. Within this model in the two-particle cluster approximation for the short-range interactions and in the mean (cid:28)eld approximation for the long-range interactions, the behavior of spontaneous polarization, longitudinal dielectric permittivity, piezoelectric and elastic characteristics, and molar heat capacity under the in(cid:29)uence of uniaxial and hydrostatic pressure and a longitudinal electric (cid:28)eld