Probing the Size Effect of Co2FeGa-SiO2@C Nanocomposite Particles Prepared by a Chemical Approach

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• 作者：Changhai Wang ; Lubna Basit ; Yuriy Khalavka ; Yanzhi Guo ; Frederick Casper ; Teuta Gasi ; Vadim Ksenofontov ; Benjamin Balke ; Gerhard H. Fecher ; Carsten Snnichsen ; Yeu-Kuang Hwu ; Jey-Jau Lee ; Claudia Felser
• 刊名：Chemistry of Materials
• 出版年：2010
• 出版时间：December 28, 2010
• 年：2010
• 卷：22
• 期：24
• 页码：6575-6582
• 全文大小：1007K
• 年卷期：v.22,no.24(December 28, 2010)
• ISSN：1520-5002

文摘

In this contribution, we report the chemical synthesis of carbon coated, silica supported Co₂FeGa (Co₂FeGa-SiO₂@C) nanocomposite particles. The particle size of Co₂FeGa particles can be tuned by varying the amount of silica supports. The dependences of the crystal structure and magnetic properties on particle size have been investigated by synchrotron radiation based X-ray diffraction (XRD), X-ray absorption fine structure (XAFS) spectroscopy, transmission electron microscope (TEM), ⁵⁷Fe Mssbauer spectroscopy, and superconducting quantum interference device (SQUID). The superparamagnetic critical size of Co₂FeGa Heusler nanoparticles is found to be 17 nm by correlating the TEM derived particle size distribution to the Mssbauer spectroscopy data. The effects of silica supports and carbon coating on the formation of Co₂FeGa nanoparticles of various sizes are also discussed.