Magnetic and M枚ssbauer spectroscopy studies of NiAl_0.2Fe_1.8O₄/SiO₂ nanocomposites synthesized by sol-gel method

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• 作者：Jiaming Li ; Li Wang ; Zhaohui Bai ; Ji Li ; Jingbin Lu ; Haibo Li
• 关键词：Sol&ndash ; gel method ; Nanocomposite ; Magnetic dead layer ; Mö ; ssbauer spectroscopy
• 刊名：Journal of Magnetism and Magnetic Materials
• 出版年：March, 2014
• 年：2014
• 卷：354
• 期：Complete
• 页码：190-194
• 全文大小：796 K

文摘

The structural and magnetic properties of NiAl_0.2Fe_1.8O₄/SiO₂ nanocomposites prepared with the sol-gel method were studied by using X-ray diffraction, transmission electron microscopy, vibrating sample magnetometer, and M枚ssbauer spectroscopy. The average grain size of NiAl_0.2Fe_1.8O₄ in the nanocomposites was found to increase from 5 to 37 nm with increasing the annealing temperature from 800 to 1200 掳C while the lattice constant was almost kept a constant of ~0.833 nm. The saturation magnetization of the nanocomposites was shown to increase with increasing the grain size. The thickness of the dead layer on the surface of the ferrite grain was obtained to about (0.61卤0.02) nm. The M枚ssbauer spectra indicated the evolution of magnetic properties of NiAl_0.2Fe_1.8O₄ nanoparticles in the nanocomposites from superparamagnetic to magnetically ordered character with increasing the size of nanoparticles.