Polarization Relaxation in Triglycine Sulfate above the Curie Temperature

Abstract

Measurements of the complex dielectric constant for normal and deuterated triglycine sulfate are reported. These measurements cover a range of 20°C above the Curie temperature and frequencies up to 7.7×${10}^{10}$ cps. A frequency- and temperature-dependent relaxation of the dielectric constant was observed which first sets in around 5×${10}^7$ cps. It was found that all the observations of ${\epsilon }^{*}$ could be expressed as ${\epsilon }^{*}=\frac{C}{T-T_c}\left[f\right(\nu {\tau }_0)+ig(\nu {\tau }_0\left)\right],$ where $C$ and $T_c$ are the Curie constant and temperature; and ${\tau }_0$ is inversely proportional to ($T-T_c$). Expressions for $f\left(\nu {\tau }_0\right)$ and $g\left(\nu {\tau }_0\right)$ which give a good fit to the data were derived by assuming that each dipole has a Debye relaxation characteristic and that there is a Gaussian distribution of relaxation times, with ${\tau }_0$ being the measure of the width of the distribution.