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<p>This work targets a clear structure–property link in BaMn<sub>0.5</sub>Ti<sub>0.5</sub>O<sub>3</sub> (BMTO) by correlating sol–gel–derived crystal chemistry with temperature-dependent dielectric and electrical responses. Phase-pure rhombohedral perovskite (R3c) was confirmed by Rietveld refinement, with nanoscale crystallites (≈45–47 nm) and dense microstructure (≈124 nm grains) evidenced by XRD/SEM; EDS verified near-stoichiometric composition. Dielectric spectra (1 kHz–1 MHz, 200–320 K) show strong frequency dispersion, ε′ decreases with frequency but increase systematically with temperature, consistent with Maxwell–Wagner interfacial polarization and thermally activated hopping. AC conductivity follows Jonscher’s power law and rises with temperature, indicating small-polaron hopping and overall negative temperature coefficient of resistance behavior. Impedance and modulus analyses reveal non-Debye relaxation dominated by grain-boundary processes; Nyquist plots are well described by an R<sub>s</sub>–(R<sub>gb</sub>||CPE) equivalent circuit, with grain-boundary resistance falling from ~255 Ω (200 K) to ~55 Ω (320 K) and the relaxation frequency shifting from ~3 kHz to ~30 kHz as temperature increases, while the CPE exponent approaches unity (0.86 → 0.93), indicating more ideal capacitive behavior at higher temperatures. These results show that B-site Mn/Ti substitution and associated defect chemistry (octahedral tilts, oxygen-vacancy assisted hopping) govern polarization and transport. BMTO therefore offers thermally tunable dielectric response and semiconducting conduction desirable for capacitors, sensors, and other multifunctional electronic components.</p><p></p>

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Sol–gel synthesized BaMn0.5Ti0.5O3 perovskite: structural, dielectric, and electrical properties with temperature-dependent analysis

  • 期刊论文

  • 发表日期：

    2025年10月1日

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  • Abdullah M. Aldukhayel

摘要

This work targets a clear structure–property link in BaMn0.5Ti0.5O3 (BMTO) by correlating sol–gel–derived crystal chemistry with temperature-dependent dielectric and electrical responses. Phase-pure rhombohedral perovskite (R3c) was confirmed by Rietveld refinement, with nanoscale crystallites (≈45–47 nm) and dense microstructure (≈124 nm grains) evidenced by XRD/SEM; EDS verified near-stoichiometric composition. Dielectric spectra (1 kHz–1 MHz, 200–320 K) show strong frequency dispersion, ε′ decreases with frequency but increase systematically with temperature, consistent with Maxwell–Wagner interfacial polarization and thermally activated hopping. AC conductivity follows Jonscher’s power law and rises with temperature, indicating small-polaron hopping and overall negative temperature coefficient of resistance behavior. Impedance and modulus analyses reveal non-Debye relaxation dominated by grain-boundary processes; Nyquist plots are well described by an Rs–(Rgb||CPE) equivalent circuit, with grain-boundary resistance falling from ~255 Ω (200 K) to ~55 Ω (320 K) and the relaxation frequency shifting from ~3 kHz to ~30 kHz as temperature increases, while the CPE exponent approaches unity (0.86 → 0.93), indicating more ideal capacitive behavior at higher temperatures. These results show that B-site Mn/Ti substitution and associated defect chemistry (octahedral tilts, oxygen-vacancy assisted hopping) govern polarization and transport. BMTO therefore offers thermally tunable dielectric response and semiconducting conduction desirable for capacitors, sensors, and other multifunctional electronic components.