Abstract

The model of two-sublattice pseudospin lattice coupled mode for Rochelle salt has been modified by adding third and fourth-order phonon anharmonic interaction terms and electric field term. By using double-time temperature dependent Green's function method, expressions for shift, width, soft mode frequency, dielectric constant and loss tangent were obtained for Rochelle salt crystal. By fitting model values of physical quantities, temperature dependence of soft mode frequency, dielectric constant and loss tangent have been calculated for different fields for Rochelle salt. Theoretical results agree with the experimental results of others.

Keywords

Ferroelectrics, Greenʹs function, Soft mode, Anharmonic interaction