Experimental Study on Dielectric Relaxation in NaNO2

Abstract

The complex dielectric constant of NaNO ₂ crystal was measured in a frequency range between 1 MHz and 24 GHz from room temperature to 210°C. The measuring methods in the various frequency ranges were described in detail and especially the measuring accuracies in the complex dielectric constant and the temperature were considered closely. It was found that a dielectric dispersion occurs in the ferroelectric b direction and this dispersion obeys nearly the formula of the Debye-type with a single relaxation time above the transition point. The relaxation frequency is proportional to ( T - T ₀ ) near the transition point, where T is the temperature and T ₀ is about 162°C, and deviates from this linear relationship above ca 180°C, bending upward. In the a and c directions, any remarkable change in the dielectric constant was not observed up to 24 GHz.