Influence of sintering temperature on structural, electrical, dielectric, and magnetic properties of magnesium ferrite (MgFe2O4) ceramics prepared using powder derived via Sol-Gel auto-combustion

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

Journal of Sol-Gel Science and Technology Pub Date : 2024-07-11 DOI:10.1007/s10971-024-06472-z

Sudhanshu Kumar, K. Sreenivas

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Abstract

Polycrystalline magnesium ferrite (MgFe₂O₄) ceramics were prepared using as-prepared MgFe₂O₄ powder derived via sol-gel auto combustion method, and the influence of sintering temperature on the structural, electrical, dielectric, and magnetic properties of bulk ceramics have been examined. Ceramic microstructure with increased grain size, crystallite size, and densification is found to improve with increasing sintering temperatures (1100 to 1200 °C/4 h). Sintering conditions (temp. and time) are optimized. The influence of grain and grain boundaries (GB’s) on electrical and dielectric properties is analysed over a wide frequency range of 0.1 Hz to 1 MHz. Ceramic sintered at 1200 °C/4 h exhibit low dc conductivity (σ_dc = 2.48 × 10⁻⁹ Ω⁻¹cm⁻¹) and a stable frequency independent dielectric constant ɛ´ ~ 15. DC conductivity determined from impedance Cole-Cole plot analysis is shown to be in close agreement with the dc conductivity estimated from ac conductivity analysis using Jonscher’s power law. Saturation magnetisation (M_S) increases, and coercivity (H_C) decreases with increase in sintering temperature. In comparison to powders, the large crystallite size (117 nm) in dense ceramics is indicative of a larger domain size with (M_S = 38 emu/g), and the well-connected ceramic grains lead to a low coercive field (H_C = 21 Oe).

Graphical Abstract

Abstract Image

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烧结温度对通过溶胶-凝胶自燃法获得的粉末制备的镁铁氧体 (MgFe2O4) 陶瓷的结构、电气、介电和磁性能的影响

利用溶胶-凝胶自燃法制备的镁铁氧体粉末制备了多晶镁铁氧体（MgFe2O4）陶瓷，并研究了烧结温度对块状陶瓷的结构、电学、介电和磁学性能的影响。研究发现，随着烧结温度（1100 至 1200 °C/4 h）的升高，陶瓷微观结构的晶粒大小、晶粒尺寸和致密化程度都有所提高。对烧结条件（温度和时间）进行了优化。在 0.1 Hz 至 1 MHz 的宽频率范围内，分析了晶粒和晶粒边界（GB）对电气和介电特性的影响。在 1200 °C/4 h 下烧结的陶瓷表现出较低的直流电导率（σdc = 2.48 × 10-9 Ω-1cm-1）和稳定的与频率无关的介电常数ɛ´ ~ 15。通过阻抗科尔-科尔图分析确定的直流电导率与使用容舍幂律进行交流电导率分析估算的直流电导率非常一致。随着烧结温度的升高，饱和磁化率（MS）升高，矫顽力（HC）降低。与粉末相比，致密陶瓷的结晶尺寸大（117 nm），表明畴尺寸更大（MS = 38 emu/g），而且陶瓷晶粒连接良好，导致矫顽力场低（HC = 21 Oe）。

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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.