Abstract

Two compounds with the formula La_0.8Ba_0.1Bi_0.1FeO₃ have been prepared by the sol–gel (LBBFO-SG) and the auto-combustion (LBBFO-AC) preparation methods. The effect of the preparation method on structural, morphology, vibrational, electrical, and dielectric properties have been carried out using the X-ray diffraction (XRD), Scanning electron microscopy (SEM), and Raman and impedance spectroscopy. The Rietveld refinement of the XRD diffractograms confirms the crystallization of both compounds through the Pnma space group. Furthermore, the nano-size scale of the prepared compounds was verified by the XRD and the SEM microscopy. From the Raman study, we conclude that the vibration modes are similar to those of the pure LaFeO₃ with a slight shape change in some modes. The relaxation processes were analyzed with the Bergmann formalism to validate the presence of two relaxation processes corresponding to grains and boundary grains contributions. These relaxations have been confirmed by studying the dielectric constant also the dielectric loss tangent is used to study the ferroelectric–paraelectric phase transition at around room temperature. The activation energy for both contributions has been calculated from the impedance, the modulus, and the dielectric loss tangent and they have almost the same values. The Nyquist plots (Z″ vs. Z′) have been adjusted using two circuits in series containing each one a resistance in parallel to a CEP capacitance.

中文翻译：

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合成路线对La 0.8 Ba 0.1 Bi 0.1 FeO 3的结构，形态，拉曼，介电和电性能的影响

摘要

通过溶胶-凝胶（LBBFO-SG）和自燃（LBBFO-AC）制备方法制备了两种分子式为La _0.8 Ba _0.1 Bi _0.1 FeO _3的化合物。制备方法对结构，形态，振动，电学和介电性能的影响已使用X射线衍射（XRD），扫描电子显微镜（SEM）以及拉曼和阻抗谱进行了研究。XRD衍射图的Rietveld精细化证实了两种化合物都通过Pnma结晶空间群。此外，通过XRD和SEM显微镜检查了所制备化合物的纳米级尺寸。根据拉曼研究，我们得出结论，振动模式与纯LaFeO ₃相似。在某些模式下形状略有变化。使用Bergmann形式主义分析了弛豫过程，以验证存在两个与晶粒和边界晶粒贡献相对应的弛豫过程。这些松弛已通过研究介电常数得到了证实，并且介电损耗正切也用于研究室温附近的铁电-顺电相变。根据阻抗，模量和介电损耗正切计算出这两种作用的激活能，它们的值几乎相同。奈奎斯特图（ž “与Ž '）已在含有每一个并联的电阻到一个CEP电容串联使用两个电路调整。