Abstract We report the effect of yttrium (Y) doping on structural, optical properties and conductivity relaxation behavior of cobalt ferrite (CFO) nanoparticles prepared via citrate auto-ignition route. Microstructural analysis using XRD study confirms the growth of single phase nanocrystalline CFO, HRTEM images delineate faults in the crystal stacking sequence. UV–vis absorption spectra show a blue shift for optical band gaps of the doped samples. Impedance spectroscopy suggests that both grain and grain boundaries contribute to the conduction process. A universal power law dependence of the conductivity spectra has been observed. Scaling of the conductivity spectra resulted the conduction mechanism to be independent of composition and temperature. Stretched behavior of the dielectric response has been elucidated by Harviliak-Negami (H.N.) model based functions. Defects in the crystal structure played important role on the overall transport properties of the system.

中文翻译：

---

掺钇铁氧体钴纳米粒子：介电弛豫和载流子动力学研究

摘要 我们报告了钇 (Y) 掺杂对通过柠檬酸盐自燃路线制备的铁酸钴 (CFO) 纳米粒子的结构、光学性质和电导弛豫行为的影响。使用 XRD 研究的微观结构分析证实了单相纳米晶 CFO 的生长，HRTEM 图像描绘了晶体堆叠序列中的缺陷。UV-vis 吸收光谱显示掺杂样品的光学带隙发生蓝移。阻抗谱表明晶界和晶界都有助于传导过程。已经观察到电导率谱的普遍幂律依赖性。电导谱的缩放导致传导机制与成分和温度无关。Harviliak-Negami (HN ) 基于模型的函数。晶体结构中的缺陷对系统的整体传输特性起着重要作用。