کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1801219 | 1024563 | 2010 | 4 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Magnetism in nanoparticles of semiconducting FeSi2 Magnetism in nanoparticles of semiconducting FeSi2](/preview/png/1801219.png)
Iron disilicide has been found to exhibit superparamagnetism in nanoparticles, even though no magnetic ordering occurs in bulk. The unexpected behavior was attributed, based on magnetic studies, to chemical disorder. A lack of sextet-type signals in Mössbauer spectra supports that the observed magnetic order is confined to only a very small fraction of magnetic Fe ions. Moreover, quadrupole-splitting and isomer-shift parameters reveal a significant amount of Fe in a short-range α-FeSi2 structure, while XRD suggests an overall β-FeSi2 structure. Such a compositional heterogeneity is also reflected in a calorimetrically obtained spin-glass-like anomaly at low temperatures. Meanwhile, as the particle size decreases, specific heat and Sommerfeld constant are enhanced due to lattice softening and the emergence of surface charge density of states, respectively, in nanoparticles.
Journal: Journal of Magnetism and Magnetic Materials - Volume 322, Issue 15, August 2010, Pages 2227–2230