Chemical Synthesis and Characterization of 纬-Co2NiGa Nanoparticles with a Very High Curie Temperature

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• 作者：Changhai Wang ; Aleksandr A. Levin ; Lucia Nasi ; Simone Fabbrici ; Jinfeng Qian ; Carlos E. Viol Barbosa ; Siham Ouardi ; Julie Karel ; Franca Albertini ; Horst Borrmann ; Gerhard H. Fecher ; Claudia Felser
• 刊名：Chemistry of Materials
• 出版年：2015
• 出版时间：October 27, 2015
• 年：2015
• 卷：27
• 期：20
• 页码：6994-7002
• 全文大小：510K
• ISSN：1520-5002

文摘

We report the first study on the chemical preparation, structural characterization, and magnetic properties of Co₂NiGa nanoparticles (NPs) of a single 纬-phase (纬-Co₂NiGa). The 纬-Co₂NiGa NPs were prepared by impregnation in colloidal silica followed by high temperature annealing under hydrogen atmosphere. The crystal structure of tetragonal 纬-Co₂NiGa was confirmed by selected area electron and X-ray diffraction studies. Energy-dispersive X-ray spectroscopy mapping and X-ray absorption near edge structure data provided evidence for the successful preparation of the intermetallic NPs and the absence of Co, Ni, Co鈥揘i, or metal-containing impurity phases. Extended X-ray absorption fine structure spectroscopy data confirmed the formation of the 纬-Co₂NiGa phase by examining the atomic environments surrounding Co, Ni, and Ga. The Co₂NiGa NPs are ferromagnetic with a high saturation magnetization, which is consistent with the theoretical model. 纬-Co₂NiGa NPs exhibit a very high Curie temperature (鈮?139 K), which make them promising candidates for high temperature magnetically activated nanoscale devices.