Diffuse dielectric anomaly of (Na0.5K0.5Bi)0.5TiO3 crystal at high temperature

摘要

This paper investigates the dielectric properties of (Na0.5K0.5Bi)0.5TiO3 crystal at intermediate frequencies (1kHz≤ f ≤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 Eτ 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.