Temperature and size dependence of magnetic and electron magnetic resonance parameters of Fe nanoparticles embedded in an amorphous SiO2 matrix

Temperature dependence (5 K to 300 K) of the magnetic properties of two Fe/SiO2 (15/85) nanocomposites with Fe particle size D ≃ 17 nm and 30 nm is reported using magnetometry and electron magnetic resonance (EMR) spectroscopy. Structural characterization of the samples, done by X-ray diffraction, T...

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Veröffentlicht in:Journal of applied physics 2011-04, Vol.109 (7)
Hauptverfasser: Singh, V., Seehra, M. S., Huggins, F. E., Shah, N., Huffman, G. P.
Format: Artikel
Sprache:eng
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Zusammenfassung:Temperature dependence (5 K to 300 K) of the magnetic properties of two Fe/SiO2 (15/85) nanocomposites with Fe particle size D ≃ 17 nm and 30 nm is reported using magnetometry and electron magnetic resonance (EMR) spectroscopy. Structural characterization of the samples, done by X-ray diffraction, TEM, and Mössbauer spectroscopy shows the presence of α-Fe, amorphous SiO2, and some nanosize Fe3+ oxides. Both samples are ferromagnets in the 5 K to 370 K range with coercivity HC(30 nm) > HC(17 nm). In EMR studies, a single resonance line near g = 2.2 characteristic of α-Fe is observed in both samples at 300 K, with linewidth ΔH(30 nm) > ΔH(17 nm). With decreasing temperature, the EMR line shifts to lower fields and broadens, which is similar to observations in other nanoparticle systems.
ISSN:0021-8979
1089-7550
DOI:10.1063/1.3537942