Antiferromagnetic ordering in NdAuGe compound

The compound NdAuGe was investigated by means of electrical resistivity, ρ(T), magnetic susceptibility, χ(T), magnetization, σ(μ0H), and specific heat, C_p(T), measurements. Powder X-ray diffraction studies confirm a hexagonal LiGaGe-type structure with space group P6₃mc (No. 186). ρ(T) data show normal metallic behaviour and a tendency toward saturation at higher temperatures. The low temperature ρ(T) data indicate a phase transition around 3.8K. The low field dc χ(T) data show an antiferromagnetic anomaly associated with a Néel temperature at T _N=3.7K close to the phase transition observed in ρ(T) results. At higher temperatures, χ(T) follows the paramagnetic Curie-Weiss behaviour with an effective magnetic moment μeff=3.546(4) μB and a paramagnetic Weiss temperature of θp=-6.1(4)K. The value obtained for μ_eff is close to the value of 3.62 μ_B expected for the free Nd³⁺-ion. σ(μ0H) shows a linear behaviour with applied field up to 3T with an evidence of metamagnetic behaviour above 3T. C_p(T) confirms the magnetic phase transition at T_N=3.4K. The 4f-electron specific heat indicates a Schottky-type anomaly around 16.5K with energy splitting δ1=25.8(4) K and δ2=50.7(4) K of the Nd ³⁺(J=9/2) multiplet, that are associated with, respectively, the first and second excited states of the Nd³⁺-ion.