aFe Z型钡铁氧体纳米复合材料的电磁微波吸收性能外文翻译.docx

Magnetic and electromagnetic wave absorption properties of -Fe/Z-type Ba-ferrite nanocomposites Jiu Rong Liu, Masahiro Itoh, and Ken-ichi Machidaa Center for Advanced Science and Innovation, Osaka University Suita, Osaka565-0871, Japan (Received 16 August 2005; accepted 6 December 2005; published online 7 February 2006) The saturation magnetization values (Ms) of -Fe / Ba3Co1.8Fe23.6Cr0.6O41 nanocomposites prepared by mechanically alloying-Fe with Ba3Co1.8Fe23.6Cr0.6O41 powders increased with increasing the concentration of-Fe.-Fe / Ba3Co1.8Fe23.6Cr0.6O41 nanocomposites showed higher coercivity values than а-Fe and Ba3Co1.8Fe23.6Cr0.6O41 because of the effects of shape anisotropy and exchange bias. The resin compacts with 33.5 vol% -Fe/Ba3Co1.8Fe23.6Cr0.6O41 (38, 70, 85 vol% а-Fe) powders provided good electromagnetic wave absorption performances in ranges of 7.5-16.0,5.4-10.5, and 4.3-8.3 GHz over the absorber thicknesses of 1.3–2.5, 1.6–3.0, and 1.7–3.2 mm, respectively. ? 2006 American Institute of Physics. [DOI: 10.1063/1.2170402] Ferrites, as conventional electromagnetic (EM) wave absorbing materials, have been widely studied from megahertz to igahertz (GHz) range because of their strong magnetism and high electric resistivity[1–3]. For EM wave applications there is an increasing interest in using ferrite-polymer ?lms rather than bulk ferrites. But, the thickness of ferrite-polymer ?lms has to be thick for ef?cient EM wave absorption, since it is dif?cult to increase the permeability values in GHz range owing to Snoek’s limit for ferrites. Comparing with ferrites, metallic magnetic materials have large saturation magnetization values and their Snoek’s limit is at a high frequency level[4]. Consequently, the values of complex permeability can remain still high in the high frequency range. Therefore, it is possible to make thinner absorbers from metallic magnetic materials than those of ferrites in GHz range[5]. However, metallic magnetic materials have high el