The Effect of D- and DL- Tyrosine Admixture on Dielectric Properties of TGS Crystals

Single crystals of TGS admixtured with L and DL- tyrosine (abbreviated as LTyrTGS and DLTyrTGS) were grown from a solution containing 0.7, 1 and 1.4 wt% of tyrosine relative to pure TGS. Temperature measurements (5 - 340 K) of permittivity l and loss tangent tg i of the samples were performed at selected frequencies of the measuring field varied from 1 kHz to 13 MHz. The values of spontaneous polarization P s , coercive field E c and bias field E b were obtained from the hysteresis loop. With increasing concentration of the dopands in the admixtured crystals, the values of l max and tg i max decreased, while that of the bias field and coercive field increased, and the Curie temperature revealed insignificant changes. The domain structure observations proved a refinement of the domain structure relative to that in pure TGS crystals and a decrease in the time of spontaneous ageing. The actual amount of the admixtures in the crystals was determined by UV spectroscopy.

Keywords

• Ferroelectrics,
• Dielectric Properties,
• Admixtures