Nanotechnology manufacturing is rapidly developing and promises that the essential changes will have significant commercial and scientific impacts be applicable in an extensive range of areas. In this area, cobalt ferrite nanoparticles have been considered as one of the competitive candidates. The present study is based on the investigation of the effect of rare-earth (RE) incorporation on the physical properties of CoFe2O4. Rare-earth ions doped cobalt ferrites with composition CoRE0.025Fe1.975O4 where RE are Ce, Er and Sm have been synthesized by citrate auto combustion technique. Characterization is achieved using X-Ray diffraction (XRD) technique for structural analysis. The obtained data show that the samples exhibit a single-phase spinel structure. RE is successfully substituted into the spinel lattice without any distortion and it acts as inhibiting agent for grain growth. Room temperature M–H curves exhibit ferrimagnetism behavior with a decrease in saturation magnetization and coercivity indicating these materials can be applicable for magnetic data storage and magneto-recording devices. The electrical conductivity is studied as a function of frequency in the temperature range of 300–700 K. The conduction mechanism is attributed to the hopping mechanism. The Seebeck coefficient S is found to be positive for Ce indicating that Co/Ce ferrite behaves as a p-type semiconductor. While it is fluctuated between positive and negative for Er/Sm-doped samples throughout the studied temperature range. The cobalt doped with Er3+ and Sm3+ exhibits degenerated semiconductor trends at higher temperatures. Such data offer a new opportunity for optimizing and improving the performance of cobalt ferrite where the physical properties are decisive.

中文翻译：

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稀土取代纳米CoFe2O4物理性能对比研究

纳米技术制造正在迅速发展，并承诺基本变化将产生重大的商业和科学影响，适用于广泛的领域。在该领域，钴铁氧体纳米颗粒被认为是具有竞争力的候选材料之一。本研究基于稀土 (RE) 掺入对 CoFe2O4 物理特性的影响的调查。通过柠檬酸盐自燃技术合成了稀土离子掺杂的钴铁氧体，其组成为 CoRE0.025Fe1.975O4，其中 RE 是 Ce、Er 和 Sm。使用 X 射线衍射 (XRD) 技术进行结构分析来实现表征。所得数据表明样品呈现单相尖晶石结构。稀土成功地取代到尖晶石晶格中而没有任何变形，它作为晶粒生长的抑制剂。室温 M-H 曲线表现出亚铁磁性，饱和磁化强度和矫顽力降低，表明这些材料可适用于磁性数据存储和磁记录设备。在 300-700 K 的温度范围内，电导率作为频率的函数进行研究。传导机制归因于跳跃机制。发现塞贝克系数 S 对于 Ce 为正值，表明 Co/Ce 铁氧体表现为 p 型半导体。虽然在整个研究温度范围内，Er/Sm 掺杂样品在正负之间波动。掺杂有 Er3+ 和 Sm3+ 的钴在较高温度下表现出退化的半导体趋势。这些数据为优化和提高钴铁氧体性能提供了新的机会，其中物理特性是决定性的。