IMPEDANCE AND MODULUS SPECTROSCOPY CHARACTERIZATION OF SODIUM-BISMUTH TITANATE-BASED LEAD-FREE FERROELECTRIC MATERIALS

摘要

In this paper, we present impedance spectroscopy of Sodium Bismuth Titanate-based materials belonging to (1-x)Na_(1/2)Bi_(1/2)TiO_(3-x)BaTiO_3 (x = 0.04) (NBT-BT) system. NBT-BT ceramics are prepared by high temperature solid-state reaction method. X-ray diffraction technique showed single-phase polycrystalline sample with an ABO3 perovskite structure. Dielectric behavior and the impedance relaxation were investigated in a wide range of temperature (room temperature (RT) -500cC) and frequency (1 kHz-1 MHz). A broad dielectric constant peak was observed over a wide temperature range around the phase transition temperature. The complex impedance plot exhibited one impedance semicircle identified over the frequency range of 1 kHz-1 MHz, which is explained by the grain effect of the bulk. The centers of the impedance semicircles lie below the real axis, which indicates that the impedance response is a Cole-Cole type relaxation.