Theoretical Study of Ferroelectric Triglycine Sulphate (TGS) Crystal in External Electric Fields

Abstract

A modified two sub-lattice pseudospin-lattice coupled mode model of Mitsui et al [Phys. Rev., 111 (1958) 1259] by adding third, fourth order phonon anharmonic interaction and external electric field terms has been applied to ferroelectric triglycine sulphate crystal. Electric field dependence of ferroelectric, dielectric and acoustical properties has been studied. With the help of double time temperature dependent Green's function method, expressions for shift, width, soft mode frequency, dielectric constant, loss tangent and acoustic attenuation have been derived. Numerically calculations have been made and results have been compared with experimental data reported by Bye et al [Ferroelectrics 4 (1974) 243] and Shreekumar et al [Ferroelectrics 160 (1994) 23] for TGS crystal and a good agreement has been observed.

Pyroelectric and dielectric energy conversion – A new view of the old problem

“…The dependence of the dielectric permittivity on temperature and the electric field intensity for TGS crystals was subject of many experimental and theoretical studies, for instance [41][42][43][44][45]. Both phenomenological, microscopic considerations and experimental results say that with the rising electric field intensity the dielectric permittivity decreases, and an influence of the electric field on the permittivity strengthened as the temperature was approaching the phase transition temperature.…”

“…The dependence of the dielectric permittivity on the electric field for TGS crystals is shown in Fig. 6 basing on data from work [45]. A slight electric field is applied to the converter at temperature in the vicinity of the phase transition (point 1 in Fig.6) during the cycle described in the previous section.…”