Temperature dependence of ferroelectric mode frequency, dielectric constant and loss tangent in PbHAsO₄ crystal

Abstract

The ferroelectric transition of PbHAsO₄ crystal has been studied using two sublattice pseudospin-lattice coupled mode model with addition of third-order and fourth-order phonon anharmonic interactions terms. With the help of double-time thermal Green’s function method, expressions for ferroelectric mode frequency, dielectric constant and dielectric loss tangent have been derived. By fitting model values of physical quantities, temperature dependence of ferroelectric mode frequency, dielectric constant and loss tangent have been numerically calculated for PbHAsO₄ crystal. Theoretical results have been compared with correlated experimental results of Arend <i>et al.</i>¹⁹. The results obtained in present study are in good agreement with experimental results.