Effect of silica coating on the structural, dielectric, and magnetic properties of maghemite nanoparticles

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	Effect of silica coating on the structural, dielectric, and magnetic properties of maghemite nanoparticles
	Nadeem, K ; Ali, L ; Gul, I ; Rizwan, S ; Mumtaz, M
刊名	JOURNAL OF NON-CRYSTALLINE SOLIDS
	2014
卷号	404 页码:72
关键词	Nanoparticles Dielectrics: magnetic properties Maghemite
ISSN号	0022-3093
通讯作者	Nadeem, K (reprint author), Int Islamic Univ, Dept Phys, Mat Res Lab, H-10, Islamabad, Pakistan.
中文摘要	Influence of silica (SiO2) coating concentration (x) = 0, 15, 30, 45, and 60% on structural, dielectric, and magnetic properties of maghemite nanopartides has been studied. X-ray diffraction analysis confirmed the cubic inverse spinet structure for the samples with x = 0, 15 and 30%, while x = 45 and 60% samples show amorphous behavior. Both average crystallite size and lattice constant were decreased with SiO2 concentration. Scanning electron microscopy images showed that the nanoparticles are spherical in shape and self-organized in leaf-like shape. Fourier transform infrared spectroscopy analysis confirmed the formation of maghemite and SiO2 phases for all the samples. At higher SiO2 concentration, vibrational bands of maghemite were suppressed and some bands overlapped with the SiO2 bands. Dielectric parameters such as dielectric constant and loss tangent were decreased with increasing frequency and became constant at higher frequencies. However, ac conductivity showed an opposite trend with higher values at higher frequencies. Dielectric properties have been explained using Koop's and Maxwell-Wagner models. Nanoparticles with x = 30% SiO2 concentration showed the highest dielectric constant with reduced magnetization. Dielectric properties also showed non-monotonic dependency on the SiO2 concentration. Bare nanopartides got high saturation magnetization close to bulk value due to larger average crystallite size while, nanoparticles with higher SiO2 concentration exhibited smaller magnetization and higher coercivity which is attributed to their smaller average crystallite size. In summary, SiO2 concentration has significant effects on the structural, dielectric, and magnetic properties of maghemite nanopartides and can be used to get suitable ferrite/SiO2 nanocomposites for different applications. (C) 2014 Elsevier B.V. All rights reserved.
资助信息	Higher Education Commission (HEC) of Pakistan
语种	英语
公开日期	2015-04-14
内容类型	期刊论文
源URL	[http://ir.iphy.ac.cn/handle/311004/59238]
专题	物理研究所_物理所公开发表论文_物理所公开发表论文_期刊论文
推荐引用方式 GB/T 7714	Nadeem, K,Ali, L,Gul, I,et al. Effect of silica coating on the structural, dielectric, and magnetic properties of maghemite nanoparticles[J]. JOURNAL OF NON-CRYSTALLINE SOLIDS,2014,404:72.
APA	Nadeem, K,Ali, L,Gul, I,Rizwan, S,&Mumtaz, M.(2014).Effect of silica coating on the structural, dielectric, and magnetic properties of maghemite nanoparticles.JOURNAL OF NON-CRYSTALLINE SOLIDS,404,72.
MLA	Nadeem, K,et al."Effect of silica coating on the structural, dielectric, and magnetic properties of maghemite nanoparticles".JOURNAL OF NON-CRYSTALLINE SOLIDS 404(2014):72.