The effect of hydrostatic pressure on thermodynamic characteristics of NH_3CH_2COOH·H_2PO_3 type ferroelectric materials

Abstract

The model of NH_3CH_2COOH·H_2PO_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.

Keywords

• ferroelectrics
• phase transition
• dielectric permittivity
• piezoelectric coefficients
• hydrostatic pressures