Diffuse dielectric anomaly of (Na_0.5K_0.5Bi)_0.5TiO₃ crystal at high temperature

This paper investigates the dielectric properties of (Na_0.5K_0.5Bi)_0.5TiO₃ crystal at intermediate frequencies (1kHz \leq f \leq 1MHz) in the temperature range of 30--560℃. A pronounced high-temperature diffuse dielectric anomaly has been observed. This dielectric anomaly is shown to arise from a Debye-like dielectric dispersion that slows down following an Arrhenius law. The activation energy E_\tau obtained in the fitting process is about 0.69eV. It proposes that the dielectric peak measured at low frequency above 400℃ is not related to the phase transition but to a space-charge relaxation.