Abstract We have synthesized single phase Ni+2-Co+2 substituted bismuth copper titanate (Bi2/3Cu3Ti4O12) electroceramic using the sol-gel autocombustion method. The XRD patterns reveal that the prepared BCTO electroceramic are of single phase without the presence of any other phases such as CuO or TiO2. FESEM micrographs show particles with well-defined cubic shape of bismuth copper titanate ceramics. EDX spectra shows all the chemical elements of the prepared composition, this confirm the stoichiometry and the purity of the synthesized electroceramic. The optical band gap study was carried out using UV–Vis–NIR spectroscopy in the region 225–1000 nm and the highest value of 3.63 eV was observed in the sample having x = 0.1. The dielectric response and impedance spectroscopy of the electroceramic were discussed based on Debye-type relaxation process and Maxwell-Wagner model. The sample having x = 0.0 shows the highest dielectric constant (3800) at room-temperature and a frequency of 42 Hz as compared to x = 0.1 and x = 0.2. The Cole-Cole plots of complex impedance and complex electric modulus indicate that grain-boundary resistance is the major contributor to the dielectric response of the prepared BCTO electroceramic.

中文翻译：

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Ni2+-Co2+ 取代的钛酸铋铜 (BCTO) 的晶体结构细化、光学特性、介电响应和阻抗谱

摘要 我们采用溶胶-凝胶自燃法合成了单相Ni+2-Co+2 取代的钛酸铋铜(Bi2/3Cu3Ti4O12) 电瓷。XRD 谱表明，制备的 BCTO 电瓷是单相的，不存在任何其他相，如 CuO 或 TiO2。FESEM 显微照片显示钛酸铋铜陶瓷颗粒具有明确的立方体形状。EDX 光谱显示了所制备组合物的所有化学元素，这证实了合成电瓷的化学计量和纯度。使用紫外-可见-近红外光谱在 225-1000 nm 范围内进行光学带隙研究，在 x = 0.1 的样品中观察到最高值 3.63 eV。基于Debye型弛豫过程和Maxwell-Wagner模型讨论了电陶瓷的介电响应和阻抗谱。与 x = 0.1 和 x = 0.2 相比，x = 0.0 的样品在室温和 42 Hz 的频率下显示出最高的介电常数 (3800)。复阻抗和复电模量的 Cole-Cole 图表明晶界电阻是制备的 BCTO 电陶瓷介电响应的主要贡献者。