The structural and dielectric properties of Na_0.5Bi_0.5TiO₃ (NBT) ceramics and crystals have been investigated and are compared to that of Pb(Zr_0.55Ti_0.45)O₃ (PZT55/45) and Pb(Mg_1/3Nb_2/3)_0.72Ti_0.28O₃ (PMNT 72/28) ceramics. X‐ray diffraction (XRD) profiles for (100), (110), (111), (200), (220), and (222) (referred to cubic structure) reveal that the monoclinic structure with Cc space group exists both in the NBT single crystal and ceramics. The diffraction profile obtained with high resolution laboratory XRD for the NBT single crystal can be well described, using Cc model instead of R3c model. The dielectric constant of NBT below T_hump shows some similarity to that of PZT45/55 ceramics below 50°C in which oxygen octahedron rotations cause the frequency dispersion of the dielectric constant. The temperature‐dependent dielectric constant for NBT can be deconvolved into two independent processes. The lower temperature process shows a typical relaxor characteristic and follows the Vogel‐Fulcher relationship. The other process at higher temperature shows less frequency‐dependent behavior. Comparing the dielectric constant of NBT with that of PZT55/45 and PMNT72/28 reveals that both oxygen octahedral rotations and random electric fields play an important role in the frequency dispersion of the dielectric constant for NBT relaxor feroelectric.

中文翻译：

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TiO6八面体旋转和随机电场对Na0.5Bi0.5TiO3的结构和性能的综合影响

研究了Na _0.5 Bi _0.5 TiO ₃（NBT）陶瓷和晶体的结构和介电性能，并将其与Pb（Zr _0.55 Ti _0.45）O ₃（PZT55 / 45）和Pb（Mg _1/3 Nb _{2）进行了比较。 / 3}）_0.72 Ti _0.28 O ₃（PMNT 72/28）陶瓷。（100），（110），（111），（200），（220）和（222）（称为立方结构）的X射线衍射（XRD）曲线表明，单斜结构具有CNBT单晶和陶瓷中都存在c空间群。使用C c模型而不是R 3c模型，可以很好地描述用高分辨率实验室XRD获得的NBT单晶的衍射曲线。NBT的以下介电常数Ť_驼峰与50°C以下的PZT45 / 55陶瓷具有一些相似之处，其中氧八面体的旋转会引起介电常数的频率色散。NBT的温度相关介电常数可以分解为两个独立的过程。较低温度的过程显示出典型的弛豫特性，并遵循Vogel-Fulcher关系。较高温度下的其他过程显示出较少的频率相关行为。将NBT的介电常数与PZT55 / 45和PMNT72 / 28的介电常数进行比较，发现氧八面体旋转和随机电场都在NBT弛豫铁电体的介电常数频率分散中起重要作用。