Impact of CeO2 additive on the temperature and frequency-dependent relaxation and conduction mechanism of BNT-BT ceramic

• Published in: Journal of materials science. Materials in electronics 2024-07, Vol.35 (21), p.1482, Article 1482
• Main Authors: Sahoo, S., Badapanda, T., Nayak, P., S.K.Rout, Tripathy, S. N.
• Format: Article
• Language: English
• Subjects: Barium titanates; Bismuth titanate; Ceramics; Cerium oxides; Characterization and Evaluation of Materials; Chemistry and Materials Science; Conduction heating; Dielectric properties; Diffraction patterns; Frequency analysis; Frequency variation; Grain boundaries; Impact analysis; Materials Science; Nyquist plots; Optical and Electronic Materials; Parameter modification; Physics; Spectrum analysis; Temperature; Temperature dependence; Unit cell
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-024-13239-3

The present research work reveals the electrical relaxation and conduction mechanism of CeO 2 modified 0.92(Bi 0.5 Na 0.5 TiO 3 )-0.08(BaTiO 3 ) ceramic (named as BNT-8BT-xCe; x  = 0.0 ≤ x ≤ 0.04) synthesized by solid-state sintering method. The structural investigation using X-ray diffraction (XRD) pattern and Rietveld refinement confirms that dual phases of rhombohedral and tetragonal were maintained in all the samples. The non-linear shifting of peaks and the unit cell volume indicates the different site occupancy of Ce ions in the BNT-8BT ceramic. The modification in the microstructure also indicates the different site occupancy of the dopant. The frequency and temperature variant relaxation and conduction mechanism were analyzed using impedance spectroscopy. The variation in the real part of the impedance and the nature of the imaginary part of the impedance highlights the different roles of the Ce in BNT-8BT ceramic. The Nyquist plot shows the NTCR (negative temperature coefficient of resistance) behavior in all compositions and the grain and grain boundary resistance values were figured out using a suitable model. The frequency variant ac conductivity was fitted with power law equations and the fitting parameters were analyzed. The activation energy associated with the relaxation and conduction mechanism was obtained from the Arrhenius equations. All the obtained parameters were correlated to the impact of Ce in the BNT-BT ceramic.