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论文类型：期刊论文

发表时间：2008-03-01

发表刊物：JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

收录刊物：SCIE、EI

卷号：320

期号：6

页面范围：1106-1111

ISSN号：0304-8853

关键字：iron and nickel nanoparticle; core/shell structure; microwave absorption property

摘要：Iron ( Fe) and nickel (Ni) nanoparticles were prepared by the DC arc-discharge method in a mixture of hydrogen and argon gases, using bulk metals as the raw materials. The microstructure of core/shell (metal/ metal oxide) in nanoparticle formed after in situ passivation process. The complex electromagnetic parameters (permittivity epsilon(r) = epsilon(r)' + i epsilon(r)'' and permeability mu(r) = mu(r)' + i mu(r)'') of the paraffin-mixed nanocomposite samples ( paraffin: nanoparticles 1: 1 in mass ratio) were measured in the frequency range of 2 - 18 GHz. The polarization mechanisms of the space charge and dipole coexist in both the Fe and Ni nanoparticles. The orientational polarization is a particular polarization for Fe nanoparticles and brings a relatively higher dielectric loss. Natural resonance is the main reason for magnetic loss and the corresponding frequencies are 11.6 and 5.2GHz for the Fe and Ni nanoparticles, respectively. The paraffin composite with Fe nanoparticles provided excellent microwave absorption properties ( reflection loss < - 20 dB) in the range 6.8 - 16.6GHz over the absorber thickness of 1.1 - 2.3 mm. (c) 2007 Elsevier B. V. All rights reserved.