Magnetic, Thermal and Transport Properties of CeNiGa2

We have measured the electrical resistivity ρ , thermoelectric power S , Hall coefficient R H , magnetic susceptibility χ , magnetization M and specific heat C of CeNiGa 2 and LaNiGa 2 polycrystalline samples. For CeNiGa 2 , an antiferromagnetic (AF) transition was found at T N =4 K. The γ value of 490 mJ/K 2 mol at T ≪ T N indicates the enhanced electron mass even in the AF state. At the same temperature region, ρ shows a T 2 dependence, the coefficient of which follows the Kadowaki-Woods plot. From C ( T ), it is found that the first excited doublet is lying at ∼30 K and the Kondo temperature has the same order. The observed broad peaks in ρ at 20 K and S at 12 K are explained by the combination of the crystal field and the Kondo effect. LaNiGa 2 shows a bulk superconductivity with the transition temperature of 2.0 K.