A comprehensive study on the structure, microstructure and electrical properties of a Dy-doped LaBiO3 ceramic for thermistor application

Abstract

In this work, the synthesis of dysprosium (Dy)-substituted lanthanum bismuth oxide (LaBi_0.95Dy_0.05O₃, LBDO) via solid-state reaction and its structural, microstructural, dielectric, and conductivity characterizations are systematically investigated. MADU Rietveld refinement of the X-ray diffraction data confirms that the compound exhibits an orthorhombic crystal structure at room temperature, with an average crystallite size of 49.1 nm, micro lattice strain of 0.000876, and dislocation density of 4.14 × 10¹⁴ m⁻². Scanning electron microscopy (SEM) analysis reveals a uniform grain distribution across the sample surface, which may contribute to improved electrical conductivity. Furthermore, energy-dispersive X-ray spectroscopy (EDX) verifies the presence of all constituent elements (La, Bi, Dy, and O) in both weight and atomic percentages within the prepared material. The investigation of dielectric properties as a function of temperature and frequency indicates the presence of Maxwell–Wagner type dielectric dispersion. Impedance analysis confirms the negative temperature coefficient of resistance (NTCR) behavior, while modulus spectroscopy reveals a non-Debye type relaxation process. The ac conductivity study suggests a thermally activated hopping mechanism in the material. Moreover, both Nyquist and Cole–Cole plot analyses validate its semiconducting nature, making it a promising candidate for energy storage device applications. Additionally, the resistance–temperature relationship confirms an NTC thermistor characteristic, highlighting its potential use in temperature sensor devices.