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<p>The electrical transport and relaxation dynamics of La<sub>0.6</sub>Sm<sub>0.1</sub>Ba<sub>0.3</sub>Mn<sub>0.8</sub>Al<sub>0.2</sub>O<sub>3</sub> manganite were investigated by complex impedance spectroscopy over a wide temperature range of 80–400&#xa0;K and frequency range of 100&#xa0;Hz–5&#xa0;MHz. AC conductivity follows Jonscher’s double power law at low temperatures and Jonscher’s power law at high temperatures. The temperature dependence of the frequency exponent suggests a crossover between different conduction models: NSPT and CBH at low temperatures and OLPT at high temperatures. Analysis of the DC conductivity highlights different conduction regimes: Mott-VRH at low temperature, adiabatic SPH at high temperature, and SE-VRH and NSH between <i>θ</i><sub>D/4</sub> and <i>θ</i><sub>D/2</sub>. Analysis of thermal and frequency evolution of conductivity reveals the appearance of a critical frequency <i>f</i><sub>c</sub>, highlighting a transition from localized to more delocalized charge carrier transport. The dielectric response and electric modulus analyses reveal a distribution of relaxation times attributed to significant contributions from interfacial polarization and charge carrier dynamics. The observed negative permittivity, at high frequencies and temperature, is attributed to an inductive contribution. The impedance spectra were successfully described using an equivalent electrical circuit supporting this interpretation. The time–temperature superposition analysis highlights a break in the universality of relaxation processes below 200&#xa0;K, followed by a perfect superposition of spectra at higher temperatures. These results provide a comprehensive description of the electrical transport and dielectric relaxation behavior of the disordered La<sub>0.6</sub>Sm<sub>0.1</sub>Ba<sub>0.3</sub>Mn<sub>0.8</sub>Al<sub>0.2</sub>O<sub>3</sub> manganite.</p>

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Competing charge transport mechanisms and non-debye dielectric relaxation in La0.6Sm0.1Ba0.3Mn0.8Al0.2O3 manganite

  • 期刊论文

  • 发表日期：

    2026年8月3日

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  • Walid Aloui,
  • Hayet Salhi,
  • Ali Mleiki,
  • Hedi Rahmouni

摘要

The electrical transport and relaxation dynamics of La0.6Sm0.1Ba0.3Mn0.8Al0.2O3 manganite were investigated by complex impedance spectroscopy over a wide temperature range of 80–400 K and frequency range of 100 Hz–5 MHz. AC conductivity follows Jonscher’s double power law at low temperatures and Jonscher’s power law at high temperatures. The temperature dependence of the frequency exponent suggests a crossover between different conduction models: NSPT and CBH at low temperatures and OLPT at high temperatures. Analysis of the DC conductivity highlights different conduction regimes: Mott-VRH at low temperature, adiabatic SPH at high temperature, and SE-VRH and NSH between θD/4 and θD/2. Analysis of thermal and frequency evolution of conductivity reveals the appearance of a critical frequency fc, highlighting a transition from localized to more delocalized charge carrier transport. The dielectric response and electric modulus analyses reveal a distribution of relaxation times attributed to significant contributions from interfacial polarization and charge carrier dynamics. The observed negative permittivity, at high frequencies and temperature, is attributed to an inductive contribution. The impedance spectra were successfully described using an equivalent electrical circuit supporting this interpretation. The time–temperature superposition analysis highlights a break in the universality of relaxation processes below 200 K, followed by a perfect superposition of spectra at higher temperatures. These results provide a comprehensive description of the electrical transport and dielectric relaxation behavior of the disordered La0.6Sm0.1Ba0.3Mn0.8Al0.2O3 manganite.