Dielectric Properties of Triglycine Sulphate Crystals Admixtured with L-Threonine

Abstract

The influence of L-threonine admixture on the dielectric properties of triglycine sulphate (TGS) crystals was studied. With increasing concentration of the admixture in the solution from which the crystals were grown, their maximum permittivity and spontaneous polarization were found to decrease, their Curie point was found not much different than that for pure TGS crystals (322 K), the coercive field and bias field increased. The domain structure of the obtained crystals was also studied by the liquid crystal method.

Low-Frequency Dielectric Dispersion of L-Threonine Admixtured Triglycine Sulphate Crystals (LTTGS)

“…Similar studies for TGS crystals admixtured with L-a-alanine were reported earlier [12]. This study is a continuation of the studies on the effect of L-threonine, an amino acid of the chemical formula CH 3 CH(OH)CHNH 2 COOH which differs from glycine by the presence of a C±CH 3 (OH) group, on single crystals of TGS, reported earlier [13,14].…”

“…The temperatures of these maxima depend not only on the frequency of the measuring field but also on whether the sample was in an external electric field and whether it was characterised by a bias field E b . The crystals of L-a-alanine [12] and Lthreonine [13,14] which have the bias field, do not show a maximum of e in this temperature range. A sample of TGS + 20% L-threonine characterised by the highest value of E b also did not show a maximum of e in the range from 130 to 210 K.…”

“…Moreover, for the latter sample no essential differences were noted in the course of tg d(T) recorded on heating and on cooling. According to our earlier studies [13], this sample was characterised by a fixed domain structure. After rejuvenation, in this sample we observed large domains which almost did not change in the process of spontaneous ageing [13].…”

“…According to our earlier studies [13], this sample was characterised by a fixed domain structure. After rejuvenation, in this sample we observed large domains which almost did not change in the process of spontaneous ageing [13]. On the basis of the above observations we can suppose that the tg d maxima occurring near the phase transition point are related to the domain structure of the samples studied.…”

Domain Pattern Evolution in Polarization Reversal of Telluric Acid Ammonium Phosphate Crystals

“…It should be noted that the influence of the ageing process on the domain structure dynamics has been examined in doped triglycine sulphate [6] and (CH3NH3) 5 Bi2 Br11 [7] crystals.…”