Magnetic and Transport Properties of the Kondo Lattice Compound YbPtAs

We report the electrical resistivity, magnetic susceptibility, and heat capacity studies on a new intermetallic compound YbPtAs, which crystallizes in a modified AlB_2 type structure. The Yb ions in YbPtAs are in a trivalent state and order antiferromagnetically around Néel temperatures T_\rm N1=6.5 K and T_\rm N2=2.2 K, respectively, deduced both from the magnetic susceptibility \chi(T) and heat capacity C(T) measurements. The magnetic contribution in resistivity, \rho_\rm m(T), exhibits a broad maximum at around 100 K and a logarithmic temperature dependence in the high-temperature region, indicative of the presence of the Kondo effect in YbPtAs.