The effect of hydrostatic pressure on thermodynamic characteristics of NH3CH2COOH·H2PO3 type ferroelectric materials

Abstract

The model of NH 3 CH 2 COOH·H 2 PO 3 , modified by taking into account the piezoelectric coupling between the ordering structure elements and the strains ε i , ε j , is used for investigation of the effects that appear under external pressures. Within two-particle cluster approximation, the components of polarization vector and static dielectric permittivity tensor of the mechanically clamped and free crystals, their piezoelectric and thermal characteristics are calculated. The effect of hydrostatic pressure on the phase transition and the calculated physical characteristics of the crystal is studied. A good quantitative description of experimental data for these crystals is obtained.

Deformation effects in glycinium phosphite ferroelectric

“…The model of deformed GPI crystal [38] made it possible to correctly describe polarization and components of dielectric permittivity tensor for a mechanically free and clamped crystal, its piezoelectric, elastic characteristics and heat capacity, influence of longitudinal field E y [39], hydrostatic pressure [40] and uniaxial pressures [41] on these characteristics, as well as relaxation phenomena [42].…”

Influence of Longitudinal Electric Field on Thermodynamic Properties of NH3CH2COOH·H2PO3 Ferroelectric

“…This allowed one to calculate the expressions for the spontaneous polarization vector, static dielectric permittivity tensor, piezoelectric coefficients, elastic constants, and molar heat capacity of the crystal and to obtain the good quantitative description of the experimental data for these characteristics. Moreover, on the basis of a modified model of GPI, we quantitatively properly described the influence of transverse fields and [8], hydrostatic [9] and uniaxial [10] pressures on the phase transition and thermodynamic characteristics of GPI crystal. Experimental data [11] show that, in the presence of a longitudinal field , the phase transition smears, and the temperature dependence of the longitudinal permittivity ( ) has rounded maximum.…”

Longitudinal and Transverse Electrocaloric Effects in Glycinium Phosphite Ferroelectric

“…This made it possible to calculate expressions for the spontaneous polarization, static dielectric permittivity tensor, piezoelectric coefficients, elastic constants, and molar heat capacity of the crystal and to obtain the good explanation of experimental data for these characteristics. In addition, based on a modified GPI model, the effects of transverse fields and [12] of hydrostatic [13] and uniaxial [14] pressures on the phase transition and thermodynamic characteristics of GPI crystals, as well as relexational phenomena [15], were quantitatively explained.…”