Within the modified four-sublattice pseudospin model of deformed RbHSO$_{4}$ ferroelectrics, using the Glauber method and in the mean field approximation we calculate the dynamic dielectric permittivity of a mechanically clamped crystal and explore its dependence on uniaxial pressures in wide temperature and frequency ranges. A satisfactory quantitative agreement with the experimental data is obtained.
A modified GPI model that accounts for the piezoelectric coupling between the ordered structural elements and the strains $\varepsilon_j$ has been used for studing of effects arising in GPI ferroelectrics under the action of the uniaxial stress $p_{2}$ and electric fields $E_1$ and $E_3$. The polarization vectors and components of static dielectric permittivity are calcucated in the two-particle cluster approximation for mechanically clamped crystal, and piezoelectric and thermal parameters are also determined. The influence of the simultaneous action of the stress
Within the framework of the modified proton ordering model for the quasi-one-dimensional hydrogen bonded ferroelectrics of the CsH$_2$PO$_4$ type with taking into account the linear in the strains $\varepsilon_1$, $\varepsilon_2$, $\varepsilon_3$, and $\varepsilon_5$ contributions into the energy of the proton subsystem, without tunneling, using the two-particle cluster approximation, we study the influence of uniaxial pressures $p_{i}$, hydrostatic pressure $p_{h}$, and shear stress $\sigma_{5}$ on the phase transition, polarization, transverse dielectric permittivity
The model of the glycine phosphite crystal, modified by taking into account of piezoelectric coupling of ordering structure elements with the lattice strains, is used for investigation of piezoelectric characteristics of the crystal. In the frames of two-particle cluster approximation the transverse piezoelectric coefficients are calculated. The influences of hydrostatic, uniaxial pressures, shear stresses and transverse electric fields on the transverse piezoelectric coefficients of the crystal are studied.