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

Abstract

For TGS crystals pure and admixtured with L-threonine, measurements of the permittivity ε and tg δ of the loss angle versus the measuring field frequency (varied from 1 to 104 kHz) were performed in the temperature range from 80 to 330 K. For the first time the low-frequency dielectric dispersion was observed in three temperature ranges: 180 to 210 K, 270 to 300 K and near the phase transition as the appearance of additional maxima of ε and tg δ. The interpretation of these maxima is given in combination with radiospectroscopic results. The dispersion in the three regions was interpreted as due to hindered rotation of NH3 groups of GI glycines (180 to 210 K), hindered rotation of NH3 groups of GII and GIII glycines and domain structure (270 to 300 K) and partial repolarisation of domains (near TC).