The magnetic and transport properties of a single crystal of YbNiGe with an orthorhombic TiNiSi-type structure are presented here. The experimental results indicate that YbNiGe undergoes two successive antiferromagnetic transitions at TN = 3.6K and Tm = 3.0K at zero field. The magnetic susceptibility and magnetization for the three principal axes show large anisotropy with the magnetic easy-axis along the a-axis, reflecting the orthorhombic crystal structure. The electrical resistivity for the current along the three principal axes shows a metallic behavior with a Kondo increase below around 50K. The magnetic entropy released at TN is 54% of Rln2 for the Kramers doublet ground state. The Sommerfeld coefficient γ is estimated to be 83.3mJ=mol K2 below 1K. The obtained value of A=γ2, where A is the coefficient of the T2 dependence of the resistivity at low temperatures, is larger than the universal value of the Kadowaki–Woods relation for heavy-fermion systems, i.e., A=γ2 = 1.0 × 10−5µΩ·cm(mol·K=mJ)2. Furthermore, this paper discusses the possible nature of two successive antiferromagnetic transitions of YbNiGe in comparison with related isostructural YbTGe compounds.
ASJC Scopus subject areas
- Physics and Astronomy(all)