Structural, dielectric and electrical characteristics of lead-free electro-ceramic:Bi(Ni2/3Ta1/3)O3

Abstract

A lead-free dielectric material bismuth nickel tantalite Bi(Ni2/3Ta1/3)O3(BNT), is prepared using a standard high-temperature solid-state reaction technique. The formation of a single phase BNT in orthorhombic crystal symmetry has been confirmed through X-ray structural analysis. The observation of nearly uniform and homogeneous distribution of grains with less number of voids on the surface of the pellet sample in scanning electron micrograph exhibits the good quality of the sample. Studies of dielectric parameters in a wide range of frequency and temperature provide important data for applications. The electric response investigated by impedance spectroscopy shows the effect of grains and grain boundaries in the restive and capacitive characteristics of the material. Based on the negative temperature coefficient of resistance (NTCR) characteristics of the material, studied by impedance spectroscopy technique, confirmed the semiconductor characteristics of the material at elevated temperatures. An analysis of Nyquist plots shows the existence of non-Debye type of dielectric relaxation mechanism in the sample. The charge carriers in the compound have both long and short range ordering that are again validated by the complex modulus and impedance analysis of the material. Keywords: Bi(Ni2/3Ta1/3)O3(BNT), Dielectric relaxation, Impedance Spectroscopy, Nyquist