Abstract

The present paper investigates the impedance and dielectric properties of lead free perovskites LaFe_1−xZn_xO_3−δ. For this purpose, we have analyzed the impact of substitution (0 ≤ x ≤ 0.15), temperature (350 to 800 °C) and frequency (5 Hz to 13 MHz) on the electric properties of the pristine LaFeO₃. Impedance analyses revealed the existence of two conduction mechanisms. Furthermore, the substitution improved the dielectric properties of lanthanum ferrite. Indeed, \(\varepsilon^{\prime }\) was greatly enhanced after substitution. The colossal \(\varepsilon^{\prime }\) values would certainly encourage the use of the perovskite in nonlinear optical applications and frequency multipliers. Otherwise, low dielectric losses were obtained at high frequencies resulting in low penetration depth. This finding confers to ferrites potential applications as high frequency microwave devices. For LaFe_0.85Zn_0.15O_3−δ, the short range movement of charge carriers dominates the relaxation process.

Graphic abstract

中文翻译：

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LaFe1−xZnxO3−δ 钙钛矿中巨大介电响应的研究

摘要

本论文研究了无铅钙钛矿 LaFe _{1− x} Zn _x O _{3− δ}的阻抗和介电特性。为此，我们分析了替代（0 ≤  x  ≤ 0.15）、温度（350 至 800 °C）和频率（5 Hz 至 13 MHz）对原始 LaFeO ₃电性能的影响。阻抗分析揭示了两种传导机制的存在。此外，取代提高了镧铁氧体的介电性能。事实上，\(\varepsilon^{\prime }\)在替换后得到了极大的增强。巨大的\(\varepsilon^{\prime }\)值肯定会鼓励钙钛矿在非线性光学应用和倍频器中的使用。否则，在高频下获得低介电损耗，导致低穿透深度。这一发现赋予铁氧体作为高频微波器件的潜在应用。对于 LaFe _0.85 Zn _0.15 O _{3- δ}，电荷载流子的短程移动主导了弛豫过程。

图形摘要