PrCo 2 Ga 8 is an orthorhombic quasi-skutterudite type compound which crystallizes in the CaCo 2 Al 8 structure type, with space group P bam (No. 55). The Pr 3+ ion has a site symmetry of C s which predicts a crystal electric field (CEF) level splitting into 9 singlets for J = 4. However, a phase transition at T m = 1.28 K is observed in electrical resistivity and specific heat results and is reported in this paper. The electrical resistivity shows an upturn below T m due to the superzone-gap formation. This transition is tuneable in fields and is suppressed to lower temperatures with applied magnetic fields. The electronic specific heat C p (T )/T increases below T m and reaches a value of 7.37 J/(mol K 2 ) at 0.4 K. The Sommerfeld coefficient, γ extracted from the low temperature analysis of C 4f (T )/T is 637 mJ/(mol K 2 ) indicating a possible mass enhancement of the quasiparticles. The calculated entropy value of 3.05 J/(mol K) is recovered around T m exhibiting almost 53% of Rln2, where R is the universal gas constant. Magnetic susceptibility results obeys the Curie-Weiss law for data above 100 K with an estimated effective magnetic moment, µ eff = 3.37 µ B /Pr and Weiss temperature, θ p = −124 K.

The compound NdAuGe was investigated by means of electrical resistivity, ρ(T), magnetic susceptibility, χ(T), magnetization, σ(μ0H), and specific heat, Cp(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 3.8 K. The low field dc χ(T) data show an antiferromagnetic anomaly associated with a Néel temperature at TN = 3.7 K 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 μeff is close to the value of 3.62 μB expected for the free Nd3+-ion. σ(μ0H) shows a linear behaviour with applied field up to 3 T with an evidence of metamagnetic behaviour above 3 T. Cp(T) confirms the magnetic phase transition at TN = 3.4 K. The 4f-electron specific heat indicates a Schottky-type anomaly around 16.5 K with energy splitting Δ1=25.8(4) K and Δ2=50.7(4) K of the Nd3+ (J = 9/2) multiplet, that are associated with, respectively, the first and second excited states of the Nd3+-ion.

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