ABSTRACT The double perovskite ceramic Pb1.5Mg0.5BiNbO6 is synthesized by the simplest and cheapest technique popularly known as mixed oxide route at medium temperature. The effect of ‘Mg’ doping at the A site of Pb2BiNbO6 on the crystal structure is shown from the room temperature X-ray diffraction pattern. The SEM picture of the sintered sample pellet exhibits the uniform distributions of small grains with grain walls. The temperature-dependent dielectric constant at different frequencies and the polarization study confirms the existence of ferroelectricity in the material. Impedance spectroscopy study for all the temperatures shows that the compound has only grain phenomena. The presence of hopping conduction mechanism with non- exponential type of conductivity relaxation is studied from the electric modulus analysis. The variation of ac conductivity with frequency at different temperatures follows the universal Jonscher’s power law. The temperature-dependent bulk conductivity indicates the NTCR behavior of the studied compound.

中文翻译：

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碱土金属离子取代对双钙钛矿结构和介电性能的影响

摘要 双钙钛矿陶瓷 Pb1.5Mg0.5BiNbO6 是通过最简单和最便宜的技术合成的，通常称为中温混合氧化物路线。室温 X 射线衍射图显示了在 Pb2BiNbO6 的 A 位点掺杂“Mg”对晶体结构的影响。烧结样品颗粒的 SEM 照片显示出具有颗粒壁的小颗粒的均匀分布。不同频率下随温度变化的介电常数和极化研究证实了材料中存在铁电性。所有温度的阻抗谱研究表明，该化合物仅具有晶粒现象。通过电模量分析研究了具有非指数型电导率弛豫的跳跃传导机制的存在。不同温度下交流电导率随频率的变化遵循通用的 Jonscher 幂律。随温度变化的体积电导率表明所研究化合物的 NTCR 行为。