Chemical synthesis and characterization of γ-Co2NiGa nanoparticles with a very high Curie temperature

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

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We report the first study on the chemical preparation, structural characterization, and magnetic properties of Co2NiGa nanoparticles (NPs) of a single γ-phase (γ-Co2NiGa). The γ-Co2NiGa NPs were prepared by impregnation in colloidal silica followed by high temperature annealing under hydrogen atmosphere. The crystal structure of tetragonal γ-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-Ni, or metal-containing impurity phases. Extended X-ray absorption fine structure spectroscopy data confirmed the formation of the γ-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. γ-Co2NiGa NPs exhibit a very high Curie temperature (≈1139 K), which make them promising candidates for high temperature magnetically activated nanoscale devices.

Original languageEnglish
Pages (from-to)6994-7002
Number of pages9
JournalChemistry of Materials
Issue number20
Publication statusPublished - 27 Oct 2015
Externally publishedYes

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