Dielectric Properties of Triglycine Sulphate Crystals Admixtured With D- and DL-Phenylalanine |
| J. Stankowskaa, E. Petera and M. Trybułab a Institute of Physics, A. Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland b Institute of Molecular Physics, Polish Academy of Sciences Smoluchowskiego 17, 60-179 Poznań, Poland |
| Received: January 3, 2000; revised version March 14, 2000 |
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| The paper reports studies on the effect of D-phenylalanine and DL-phenylalanine admixtures on dielectric properties and domain structure of triglycine sulphate crystals. Permittivity ε and loss tangent tgδ were measured in a wide range of temperatures (10-340 K) as a function of measuring field varied from 1 to 10000 kHz, for samples cut out from two growth pyramids (001) and (110) from triglycine sulphate crystals containing different concentrations of admixtures. A comparison of the effects of D-phenylalanine and DL-phenylalanine admixtures on dielectric properties of triglycine sulphate crystals was made. With increasing concentrations of admixtures in the crystals, the values of εmax decreased while Ec and Eb (bias field) increased, and Ps and Tc showed insignificant changes. Observations of the domain structure of the admixtured crystals by the liquid crystal method proved its refinement and irregularity. Changes in the domain structure of the crystals occurring in the process of spontaneous ageing were analysed. |
| DOI: 10.12693/APhysPolA.97.1061 PACS numbers: 77.22.-d |