Effect of Gd doping on the microstructure and electrical characteristics of Maghemite (γ-Fe₂O₃) ceramics

IF 2.3 4区材料科学 Q2 MATERIALS SCIENCE, CERAMICS

Journal of Sol-Gel Science and Technology Pub Date : 2024-10-30 DOI:10.1007/s10971-024-06598-0

Ramzi Dhahri, Majdi Benamara, Souhir Bouzidi, Sana Ben Moussa, Abdullah Yahya Abdullah Alzahrani, Kais Iben Nassar, Nassim Zahmouli, Elkenany Brens Elkenany, A. M. Al-Syadi

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Abstract

This paper presents a novel study on the microstructure and electrical properties of gadolinium (Gd) doped maghemite (γ-Fe₂O₃) nanoparticles, emphasizing their significance for advanced applications in efficient materials. X-ray diffraction analysis confirmed that both pure and doped samples crystallized in a cubic structure (P4₃32 space group) with high purity. Gd doping significantly increased crystallite size and altered particle morphology, as shown by transmission electron microscopy (TEM), which revealed larger nanoparticles with cubic shapes. Thermal analysis (TGA and DTG) indicated that higher Gd concentrations enhanced thermal instability, affecting structural integrity. FTIR spectra showed shifts in Fe-O bond vibrations, suggesting lattice distortions and increased disorder. BET measurements indicated that higher Gd doping led to greater mesoporosity and surface area, countering expectations of densification. Electrical conductivity and impedance studies revealed two distinct regions: a constant conductivity at low frequencies and an exponential increase at high frequencies, attributed to small polaron hopping. Activation energy values below 200 meV support this mechanism. Gd doping decreased overall conductivity due to disrupted atomic arrangements, increased electron scattering, and modifications in the electronic band structure. Complex impedance spectroscopy illustrated higher real impedance values for doped samples, with increased Gd concentration leading to enhanced impedance. These findings elucidate the impact of Gd on the electrical properties of maghemite nanoparticles and highlight their importance in meeting the growing demands for highly efficient technologies in energy storage and electronic devices.

Graphical Abstract

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Gd掺杂对磁赤铁矿（γ-Fe₂O₃）陶瓷微观结构和电特性的影响

本文对钆（Gd）掺杂磁赤铁矿（γ-Fe₂O₃）纳米颗粒的微观结构和电学性质进行了新的研究，强调了它们在高效材料中的先进应用意义。x射线衍射分析证实，纯样品和掺杂样品均以立方结构（P4332空间群）结晶，纯度高。透射电子显微镜（TEM）显示，Gd的掺杂显著增加了晶体尺寸，改变了颗粒形态，显示出更大的立方形状的纳米颗粒。热分析（TGA和DTG）表明，较高的Gd浓度增强了热不稳定性，影响了结构的完整性。FTIR光谱显示Fe-O键振动发生了变化，表明晶格畸变和无序性增加。BET测量表明，较高的Gd掺杂导致更大的介孔率和表面积，与致密化的预期相反。电导率和阻抗研究揭示了两个不同的区域：低频恒定的电导率和高频指数增长，归因于小极化子跳变。低于200兆电子伏的活化能值支持这一机制。由于原子排列被打乱，电子散射增加，电子能带结构改变，Gd掺杂降低了总体电导率。复杂阻抗谱表明，随着Gd浓度的增加，掺杂样品的实际阻抗值更高。这些发现阐明了Gd对磁铁矿纳米颗粒电性能的影响，并强调了它们在满足能源存储和电子设备中对高效技术日益增长的需求方面的重要性。图形抽象

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来源期刊

Journal of Sol-Gel Science and Technology 工程技术-材料科学：硅酸盐

CiteScore

4.70

自引率

4.00%

发文量

280

审稿时长

2.1 months

期刊介绍： The primary objective of the Journal of Sol-Gel Science and Technology (JSST), the official journal of the International Sol-Gel Society, is to provide an international forum for the dissemination of scientific, technological, and general knowledge about materials processed by chemical nanotechnologies known as the "sol-gel" process. The materials of interest include gels, gel-derived glasses, ceramics in form of nano- and micro-powders, bulk, fibres, thin films and coatings as well as more recent materials such as hybrid organic-inorganic materials and composites. Such materials exhibit a wide range of optical, electronic, magnetic, chemical, environmental, and biomedical properties and functionalities. Methods for producing sol-gel-derived materials and the industrial uses of these materials are also of great interest.