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<p>Nanocrystalline La₀.₇Y₀.₀₅Ba₀.₂₅MnO₃ (LYBMO) manganite was successfully synthesized via the sol–gel route, and its structural and electrical properties were systematically investigated. X-ray diffraction combined with Rietveld refinement confirms the formation of a single-phase orthorhombic structure (Pnma) with high crystallinity and an average grain size of approximately 85&#xa0;nm. The calculated tolerance factor and the reduced Mn–O–Mn bond angle (~ 165.9°) indicate a distorted perovskite lattice, which plays a crucial role in governing the electrical behavior. The dielectric response exhibits strong low-frequency dispersion attributed to Maxwell–Wagner interfacial polarization and thermally activated charge-carrier hopping, while a stable intrinsic behavior dominates at high frequencies. A comprehensive multi-formalism analysis based on dielectric permittivity (ε′, ε″), electric modulus (M′, M″), and impedance spectroscopy (Z′, Z″) reveals a consistent relaxation behavior across all representations. The temperature-dependent shift of relaxation peaks toward higher frequencies confirms the thermally activated nature of the process, further supported by an activation energy of Ea ≈ 0.198&#xa0;eV derived from Arrhenius analysis of the modulus spectra, characteristic of small-polaron hopping conduction. Moreover, the scaling of ε″, M″, and Z″ into a single master curve demonstrates a temperature-independent distribution of relaxation times, evidencing a dominant non-Debye relaxation mechanism. The combined results establish a unified picture of charge transport governed by thermally activated hopping and highlight a clear correlation between structural distortion and electrical response. These findings underline the potential of LYBMO manganite for high-temperature dielectric devices and energy-storage applications.</p>

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Correlated dielectric relaxation and impedance scaling in nanocrystalline LYBMO manganite for energy-storage applications

  • 期刊论文

  • 发表日期：

    2026年6月22日

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  • Safa Mnefgui

摘要

Nanocrystalline La₀.₇Y₀.₀₅Ba₀.₂₅MnO₃ (LYBMO) manganite was successfully synthesized via the sol–gel route, and its structural and electrical properties were systematically investigated. X-ray diffraction combined with Rietveld refinement confirms the formation of a single-phase orthorhombic structure (Pnma) with high crystallinity and an average grain size of approximately 85 nm. The calculated tolerance factor and the reduced Mn–O–Mn bond angle (~ 165.9°) indicate a distorted perovskite lattice, which plays a crucial role in governing the electrical behavior. The dielectric response exhibits strong low-frequency dispersion attributed to Maxwell–Wagner interfacial polarization and thermally activated charge-carrier hopping, while a stable intrinsic behavior dominates at high frequencies. A comprehensive multi-formalism analysis based on dielectric permittivity (ε′, ε″), electric modulus (M′, M″), and impedance spectroscopy (Z′, Z″) reveals a consistent relaxation behavior across all representations. The temperature-dependent shift of relaxation peaks toward higher frequencies confirms the thermally activated nature of the process, further supported by an activation energy of Ea ≈ 0.198 eV derived from Arrhenius analysis of the modulus spectra, characteristic of small-polaron hopping conduction. Moreover, the scaling of ε″, M″, and Z″ into a single master curve demonstrates a temperature-independent distribution of relaxation times, evidencing a dominant non-Debye relaxation mechanism. The combined results establish a unified picture of charge transport governed by thermally activated hopping and highlight a clear correlation between structural distortion and electrical response. These findings underline the potential of LYBMO manganite for high-temperature dielectric devices and energy-storage applications.