Investigation on Structural, Microstructure, Dielectric and Electrical Properties of BiVTiO 6 Ceramic for NTC Thermistor Application

In this paper, synthesis, characterization and application of the BiVTiO6 (BVTO) ceramic are studied. The preliminary analysis of XRD pattern at room temperature reveals the formation of stable solid solution with major phase of monoclinic crystal symmetry. The Goldschmidt tolerance factor was estimated to be 0.99, which confirmed the stability of the structure. The Williamson-Hall method was used to determine the average crystallite size, micro lattice strain and dislocation density, which are found to be 77 nm, 0.00126 and 1.68 × 1014 m−2, respectively. Analysis using scanning electron microscopy (SEM) shows that the sample has a homogeneous pattern of grains with well-defined grain boundaries on the surface, which can play a role in enhancing conductivity. The average grain size, calculated using ImageJ software, was found to be 2.58 µm. The sample exhibited a high agglomeration ratio of 33, indicating good microstructural quality and enhanced structural stability. The analysis of the dielectric properties as a function of frequency and temperature indicates that the dielectric dispersion is predominantly governed by the Maxwell–Wagner interfacial polarization mechanism. The negative temperature coefficient of resistance (NTCR) behavior is confirmed through impedance spectroscopy, while modulus spectroscopy reveals the presence of a non-Debye relaxation process. The study of resistance versus temperature over wide range of temperature attributes a characteristic of a PTC and NTC thermistor character, which also points to its possible use in temperature sensor equipment.