The Co2NiGa alloy with a fcc structure was synthesized by different methods, arc-melting and mechanical alloying. In contrast with the solid solution state in melted Co2NiGa, an intermetallic structure, highly ordered atomic arrangement has been verified in ball-milled sample by x-ray diffraction examination and Rietveld analysis. This ordered structure increases the saturation magnetization about 40% higher than that of solid solution sample. A highly ordered Co2NiGa intermetallic compound model was established for carrying out first-principles calculation. The obtained electronic structure and the molecular moment are quite consistent with the experimental results. The characterization of the samples prepared in different alloying processes is also reported.

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Reduced graphene oxide (rGO)/Bi2Te3 nanocomposite powders with different contents of rGO have been synthesized by a one-step in-situ reductive method. Then, rGO/Bi2Te3 nanocomposite bulk materials were fabricated by a hot-pressing process. The effect of rGO contents on the composition, microstructure, TE properties, and carrier transportation of the nanocomposite bulk materials has been investigated. All the composite bulk materials show negative Seebeck coefficient, indicating n-type conduction. The electrical conductivity for all the rGO/Bi2Te3 nanocomposite bulk materials decreased with increasing measurement temperature from 25 °C to 300 °C, while the absolute value of Seebeck coefficient first increased and then decreased. As a result, the power factor of the bulk materials first increased and then decreased, and a power factor of 1340 μWm−1K−2 was achieved for the nanocomposite bulk materials with 0.25 wt% rGO at 150 °C.