Influence of shear stress $\sigma_6$ on the phase transition and physical properties of KD2PO4 type ferroelectrics

TL;DR

This study uses a four-particle cluster approximation to analyze how shear stress $\sigma_6$ affects phase transitions and physical properties of KD2PO4 ferroelectrics, providing theoretical insights aligned with experimental data.

Contribution

It introduces a detailed theoretical model incorporating shear stress effects on KD2PO4 ferroelectrics, extending understanding of stress-induced phase behavior and properties.

Findings

Shear stress $\sigma_6$ shifts the phase transition temperature.

Theoretical results fit well with experimental data.

Stress $\sigma_6$ acts similarly to an electric field on the order parameter.

Abstract

Within the four-particle cluster approximation for the proton ordering model we study the influence of shear stress $\sigma_6$ on the phase transition, static dielectric, elastic and thermal properties of deuterated KD2PO4 type ferroelectrics. Thermodynamic potentials and physical characteristics of the crystals in the presence of stress $\sigma_6$ are calculated. Numerical analysis of the obtained results is performed, and the set of the theory parameters providing the best fit to the available experimental data is found. The $Tc-\sigma_6$ phase diagram is constructed; temperature dependences of the calculated quantities are studied, possible stress dependences are indicated. Influence of $\sigma_6$ stress is analogous to that of electric field conjugate to the order parameter.