The effect of L- and DL-Tryptophan admixtures on dielectric properties of TGS crystals

The paper reports the effect of L-Tryptophan (L-Tryp) and DL-Tryptophan (DL -Tryp) admixtures on dielectric properties of TGS crystals. Temperature mea surements (100-340 K) of permittivity epsilon and loss tangent tg delta of the samples were performed for selected frequencies of the measuring field varied from 1 to 10(4) kHz for LTrypTGS and DLTrypTGS crystals with differe nt concentrations of organic dopants. For the first time the low-frequency dielectric dispersion was observed in three temperature regions: 140 to 190 K, 230 to 260 K and near the phase transition as the appearance of addition al maxima of epsilon and tg delta. With increasing concentration of the dop ants in the admixtured crystals the values of epsilon(max), and tg delta(ma x) decreased while bias field E-b increased, and Curie temperature T-c show ed insignificant changes.