Temperature and electric field dependence of soft mode frequency, dielectric constant and loss tangent in rochelle salt crystal

883-888 A two-sublattice pseudospin lattice coupled mode model of Chaudhuri et al. [J Phys Soc Japan, 49 (1980) 609.] along with third-and fourth-order phonon anharmonic interaction terms and electric field term, has been considered. By using double-time temperature dependent Green's function method, expressions for shift, width, soft mode frequency, dielectric constant and loss tangent are 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 are seen to compare well with the experimental results of Sandy and Jones [Phys Rev, 168 (1968) 481].