Metamagnetic behavior in the new Kondo compound CePtAs

We have synthesized for the first time CePtAs and investigated the transport and magnetic properties. The electrical resistivity ρ and Hall constant R_H measured on a single crystal show a strong and peculiar anisotropy. The ρ along the c-axis is about 1300 μΩ cm at 300 K and increases with decreasing temperature like semiconductors or Kondo compounds. On the other hand, ρ along the a-axis shows a metallic behavior. Hall constant is negative for magnetic field within the c-plane, whereas its sign is positive for the magnetic field along the c-axis. From the measurement of magnetic susceptibility χ, it is revealed that CePtAs is an antiferromagnet with transition temperature T_N of 1.0 K. Below T_N, metamagnetic behavior is observed; for the magnetic field along the a-axis, magnetization increases up to 0.4 μ_B at 4 kOe, whereas for the field along the c-axis 0.7 μ_B is obtained at 10 kOe.