Dielectric Anomaly of Triglycine Sulfate in the Ferroelectric Phase: Single Crystals and Powders

Complex dielectric constants of the single crystal and the powder (∼100 µm) of TGS have been measured from 4.2 K to 340 K between 10 Hz and 100 kHz. At 1 kHz, peaks of the dielectric loss ε''( T ) associated with dielectric dispersions were observed at T f =121 K in the single crystal and T f =44 K in the powder. The activation energies of these dispersions are U =0.15 eV for the single crystal and U =0.030 eV for the powder. The strength of the dispersions diminished markedly by addition of L-α-alanine to the crystal. The decreases in T f and U in the powder are attributed to a depolarization effect.