Microstructures induced microwave resonance peak shift of Co/Al2O3 nanocomposites prepared by ball milling

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	Microstructures induced microwave resonance peak shift of Co/Al2O3 nanocomposites prepared by ball milling
	Ni, Xia 1,2; Li, Jiangong 1
刊名	Journal of Alloys and Compounds
	2013
卷号	558 页码:62-67
关键词	Nanocomposite Interface Ball milling Microstructure Microwave absorption
ISSN号	0925-8388
通讯作者	Ni, Xia
英文摘要	Microstructures play an important role in materials' functional performances. In this work, the microstructures including interfaces induced microwave resonance peak shift of Co/Al₂O₃ nanocomposites is studied. Nanosized Co/Al₂O₃ composites were successfully fabricated via direct ball milling. The hcp and fcc Co phases coexist for a long milling duration and the interface effect is prominent in the nanocomposites. The measured relative complex permittivity of the Co/Al₂O₃ nanocomposite-paraffin wax mixture indicates that a high electrical resistivity and a dielectric loss exist in the Co/Al₂O₃ nanocomposites. The dielectric loss mainly arises from the polarization of the metal/insulator interfaces. The imaginary part of the relative complex permeability of the mixture exhibits a broad resonance peak centered at 8.3 GHz which originates from the natural resonance of Co. In comparison to the reported value 6.5 GHz, the shift of the resonance peak to higher frequency can be attributed to the surface anisotropy induced by prominent interface effects, which was confirmed by NMR. The position of the resonance peak results from the competition between the surface anisotropy and the dipolar coupling interaction of the Co grains. The calculated reflection loss curves show that the reflection loss value of the Co/Al₂O₃ nanocomposite- paraffin wax mixture can reach -10 dB in a broad frequency range. The improved microwave characteristics are closely related to the microstructures, and can be tailored by controlling the content of Co and the thickness of the sample.
学科主题	材料科学与物理化学
收录类别	SCI
资助信息	the National Natural Science Foundation of China (Nos. 11175221;51071079)
语种	英语
WOS记录号	WOS:000315925600011
内容类型	期刊论文
源URL	[http://210.77.64.217/handle/362003/18224]
专题	兰州化学物理研究所_固体润滑国家重点实验室
作者单位	1.Lanzhou Univ, Sch Phys Sci & Technol, Lanzhou 730000, Peoples R China 2.Chinese Acad Sci, Lanzhou Inst Chem Phys, State Key Lab Solid Lubricat, Lanzhou 730000, Peoples R China
推荐引用方式 GB/T 7714	Ni, Xia,Li, Jiangong. Microstructures induced microwave resonance peak shift of Co/Al2O3 nanocomposites prepared by ball milling[J]. Journal of Alloys and Compounds,2013,558:62-67.
APA	Ni, Xia,&Li, Jiangong.(2013).Microstructures induced microwave resonance peak shift of Co/Al2O3 nanocomposites prepared by ball milling.Journal of Alloys and Compounds,558,62-67.
MLA	Ni, Xia,et al."Microstructures induced microwave resonance peak shift of Co/Al2O3 nanocomposites prepared by ball milling".Journal of Alloys and Compounds 558(2013):62-67.