Carbon Nanocapsule-Mediated Formation of Ferromagnetic Fe5Si3 Nanoparticles

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• 作者：Manoj K. Kolel-Veetil ; Syed B. Qadri ; Michael Osofsky ; Ramasis Goswami ; Teddy M. Keller
• 刊名：Journal of Physical Chemistry C
• 出版年：2009
• 出版时间：August 20, 2009
• 年：2009
• 卷：113
• 期：33
• 页码：14663-14671
• 全文大小：479K
• 年卷期：v.113,no.33(August 20, 2009)
• ISSN：1932-7455

文摘

Magnetic and structural characteristics were investigated for the nanoparticles of Fe₅Si₃ grown by a carbon-mediated, kinetically controlled pyrolysis of a thermosetted ferrocenylsiloxane polymeric network. Kinetics of the pyrolysis determined the volume fraction of the crystallographic phase of Fe₅Si₃ or bcc-Fe that was formed. Nanoparticles of Fe₅Si₃ were formed during pyrolysis of the network to 1000 °C at 10 °C/min, and silicon-doped bcc-Fe nanoparticles resulted when the network was ramped to 1000 °C at a slower rate of 1 °C/min. Transmission electron microscopy and X-ray diffraction studies revealed that Fe₅Si₃ nanoparticles were contained in carbon nanocapsules, and the bcc-Fe nanoparticles were associated with linear carbon fibers, an outcome of the distinct interfacial energies of the Fe−Si growth phase and carbon surface at the two pyrolysis rates. Fe₅Si₃ nanoparticles were found to be ferromagnetic with a Curie temperature of 375 K by magnetic measurements.