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題名: | Magnetism in nanoparticles of semiconducting FeSi2 | 作者: | Hamdeh, H.H.;Eltabey, M.M.;Ho, J.C.;Lee, P.C.;Chen, K.;Chen, Yang-Yuan 陳洋元 |
貢獻者: | 應物所 | 關鍵詞: | Chemical disorder; Compositional heterogeneity; Fe-ions; Iron disilicide; Low temperatures; Magnetic ordering; Magnetic orders; Magnetic studies; Quadrupoles; Shift parameters; Sommerfeld constant; XRD; Calorimetry; Iron compounds; Molybdenum; Nanoparticles; Specific heat; Spin glass; Superparamagnetism; Nanomagnetics | 日期: | 八月-2010 | 上傳時間: | 29-六月-2015 | 摘要: | 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. © 2010 Elsevier B.V. All rights reserved. | 關聯: | Journal of Magnetism and Magnetic Materials, 322(15), 2227-2230 | 資料類型: | article | DOI: | http://dx.doi.org/10.1016/j.jmmm.2010.02.015 |
Appears in Collections: | 期刊論文 |
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