کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1802574 | 1024600 | 2008 | 7 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Giant magnetic susceptibility enhancement in field-structured nanocomposites Giant magnetic susceptibility enhancement in field-structured nanocomposites](/preview/png/1802574.png)
We demonstrate through experiment and simulation that when mono-domain Fe nanoparticles are formed into chains by the application of a magnetic field, the susceptibility of the resulting structure is greatly enhanced (11.4-fold) parallel to the particle chains and is much larger than transverse to the chains. Simulations show that this significant enhancement is expected when the susceptibility of the individual particles approaches 5 in MKS units, and is due to the spontaneous magnetization of individual particle chains, which occurs because of the strong dipolar interactions. This large enhancement is only possible with nanoparticles, because demagnetization fields limit the susceptibility of a spherical multi-domain particle to 3 (MKS). Experimental confirmation of the large susceptibility enhancement is presented, and both the enhancement and the susceptibility anisotropy are found to agree with simulation. The specific susceptibility of the nanocomposite is 54 (MKS), which exceeds the highest value we have obtained for field-structured composites of multi-domain particles by a factor of four.
Journal: Journal of Magnetism and Magnetic Materials - Volume 320, Issue 18, September 2008, Pages 2221–2227