Abstract Dielectric capacitors with high recoverable energy density are in high demand for their application in electrical and electronic systems. Among lead-free dielectric materials, silver niobate (AgNbO3) has attracted growing interest due to its superior energy storage density at room temperature. The field-induced phase transition from antiferroelectric (AFE) phase to ferroelectric (FE) phase contributes to its large energy density. In this work, pure perovskite silver niobate ceramics were fabricated in an oxygen atmosphere by the solid-state reaction technique. The Pbcm orthorhombic phase of AgNbO3 was closely observed using the Rietveld refinement method to provide explanation for the origin of high spontaneous polarization within a unit cell. Local structural analysis via piezoelectric force microscopy revealed the existence of ferroelectric nano domains, which may contribute to the high energy storage efficiency (η = 99.9926%) in AgNbO3 at low electric fields. The phase transitions of AgNbO3 were also investigated via the dependence of the dielectric permittivity (e′ and e″) and loss angle tangent (tanδ) on temperatures, providing insights into the further modification of AgNbO3.

中文翻译：

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无铅钙钛矿铌酸银陶瓷的制备、结构和介电性能

摘要 具有高可恢复能量密度的介电电容器在电气和电子系统中的应用需求很大。在无铅介电材料中，铌酸银 (AgNbO3) 因其在室温下具有优异的储能密度而引起了越来越多的关注。从反铁电（AFE）相到铁电（FE）相的场致相变有助于其大的能量密度。在这项工作中，通过固态反应技术在氧气气氛中制备了纯钙钛矿铌酸银陶瓷。使用 Rietveld 精修方法仔细观察 AgNbO3 的 Pbcm 正交相，以解释晶胞内高自发极化的起源。通过压电力显微镜的局部结构分析揭示了铁电纳米域的存在，这可能有助于在低电场下 AgNbO3 中的高能量存储效率 (η = 99.9926%)。还通过介电常数（e' 和 e''）和损耗角正切（tanδ）对温度的依赖性研究了 AgNbO3 的相变，为进一步修改 AgNbO3 提供了见解。