Dielectric spectroscopy of TGS

Abstract

Ferroelectric crystal TGS has different properties in ferro phase. Five phases appear distinct down the transition point till 30 °C. Crystals were grown at 52 °C by solvent evaporation in para phase, samples were polished and silver electrode were painted. Spectrometer Alpha-A Novocontrol was used for dielectric measurements (1-10⁷ Hz), crossing Curie point from 65 °C to zero Celsius at a pace of 0.6 °C/minute. The decomposed curve ε“gives the dielectric losses and conduction losses. This component, at small frequency is huge and allow to estimate losses directly. The curve Ps²(T) shows 5 zone of temperature dependent intervals in ferro phase, from Tc to about 30 °C, where the transition is finished. The three type of relaxation: LOW, MIDDLE and HIGH, correspond to domains and to relaxation of several group in the structure. Crystal properties appear unstable on the temperature interval 46/47 °C ÷ Tc. All relaxation time behaves opposite with temperature on this interval, versus the data found upper 46/47 °C. The frequency coefficient N shows distinct ranges of linear temperature dependence on the interval 25-45 °C. On the zone 46 °C-Tc, coefficient shows a non-Arrhenius temperature dependence.

Keywords:

• TGS dielectric spectroscopy
• ferroelectric stage
• activation energies
• limited transition
• conductivities