Abstract In this work, milling effect on chemically synthesized nanocrystalline Zinc Cobaltite ( Z n C o 2 O 4 ) has been investigated and we report how the structural and electrical properties vary with the milling span. Phase pure Z n C o 2 O 4 has been successfully synthesized via simple and cost-effective co-precipitation method and then it has been milled for one, four and 8 h respectively. XRD confirms formation of single phase cubic structure for both milled and unmilled nano-powders. Different microstructural parameters has been estimated from Rietveld analysis, which shows particle size reduction from ∼29.64 nm for unmilled sample to ∼18.13 nm for 8 h milled sample. TGA-DSC curve of as prepared sample shows good temperature stability that helps to estimate the appropriate sintering temperature for the samples. TEM analysis also gives values of grain size in agreement with Reitveld analysis. Frequency dependent ac conductivity curve obeys universal Jonscher power law and temperature dependence of frequency exponent is explained by small polaron transaction. Comparable activation energies from hopping mechanism and relaxation process indicates similar transport mechanism. Superimposed scaling spectra obeys TTSP principle. AC conductivity increases with frequency as a result of hopping of the charge carriers. Smaller particles with reduced strain gives enhanced conductivity as well as enhanced value of hopping frequency. This further suggests creation of excess charge carriers in milled samples. Cole-Cole plot shows non-Debye type behaviour of the samples. The dielectric loss factor increases with lowering of particle size since smaller grains contributes to faster charge conduction.

中文翻译：

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机械研磨下化学衍生的 ZnCo2O4 电荷传输动力学的微观结构解释

摘要 在这项工作中，研究了化学合成纳米晶钴酸锌 (Z n C o 2 O 4 ) 的球磨效应，并报告了结构和电学性能如何随球磨跨度而变化。通过简单且经济高效的共沉淀法成功合成了相纯的 Z n C o 2 O 4 ，然后分别研磨了 1、4 和 8 小时。XRD 证实了研磨和未研磨纳米粉末的单相立方结构的形成。根据 Rietveld 分析估计了不同的微观结构参数，其显示粒径从未研磨样品的~29.64 nm 减小到研磨 8 小时的样品的~18.13 nm。所制备样品的 TGA-DSC 曲线显示出良好的温度稳定性，有助于估计样品的合适烧结温度。TEM 分析还给出了与 Reitveld 分析一致的晶粒尺寸值。频率相关的交流电导率曲线遵循通用的 Jonscher 幂定律，频率指数的温度相关性可以通过小极化子交易来解释。来自跳跃机制和弛豫过程的可比活化能表明类似的传输机制。叠加缩放谱遵循 TTSP 原理。由于电荷载流子的跳跃，交流电导率随频率增加。具有减小的应变的较小颗粒提供增强的导电性以及增强的跳跃频率值。这进一步表明在研磨样品中产生了过量的电荷载流子。Cole-Cole 图显示了样品的非德拜型行为。