In this paper, gadolinium-incorporated sodium bismuth titanate [Na0.5(Bi0.4Gd0.1)TiO3, NBGT] is synthesized by a conventional solid-state reaction method. The structural Rietveld analysis of the studied material was done using MAUD software, and obtained cubic crystal symmetry with space group Pm-3 m and also lattice constant a = 3.8775 Å and R-factors are Rwp (%) = 8.95115, Rb (%) = 6.6490474, Rexp (%) = 3.9524438, and \(\sigma =\) 2.2647128. The Williamson–Hall method is used to calculate an average crystallite size of 78.3 nm, a micro-lattice strain of 0.00206, and a dislocation density of \(1.63 \times {10}^{ 14} {m}^{-2}\) . The study of scanning electron microscopy (SEM) micrographs suggests a regular arrangement of grains, each measuring 1.15 µm, with well-defined grain boundaries. The FTIR study reveals the presence of Na-O, Gd-O, Bi-O, and Ti-O atomic stretching vibrations and confirms the formation of NBGT ceramic. The UV–visible study reveals the energy bandgap of 2.85 eV, which can be a suitable energy range for photovoltaic applications. The dielectric study reveals the presence of a Maxwell–Wagner type of polarization effect. The study of impedance plots reveals a negative temperature coefficient of resistance (NTCR) character, which is strongly supported by the results of Nyquist’s and Cole–Cole plots. Again, modulus analysis reveals the existence of a non-Debye type of relaxation. The variation of resistance versus temperature reveals NTC/PTC thermistor character in the low/high range of temperatures.
