Antiferromagnetic Kondo lattice in the layered compound CePd1-xBi2 and comparison to the superconductor LaPd1-xBi2

The layered compound CePd1-xBi2 with the tetragonal ZrCuSi2-type structure was obtained from excess Bi flux. Magnetic susceptibility data of CePd1-xBi2 show an antiferromagnetic ordering below 6 K and are anisotropic along the c axis and the ab plane. The anisotropy is attributed to crystal-electric-field (CEF) effects and a CEF model which is able to describe the susceptibility data is given. An enhanced Sommerfeld coefficient. of 0.191 J mol Ce-1 K-2 obtained from specific-heat measurement suggests a moderate Kondo effect in CePd1-xBi2. Other than the antiferromagnetic peak at 6 K, the resistivity curve shows a shoulder like behavior around 75 K which could be attributed to the interplay between Kondo and CEF effects. Magnetoresistance and Hall-effect measurements suggest that the interplay reconstructs the Fermi-surface topology of CePd1-xBi2 around 75 K. Electronic structure calculations reveal that the Pd vacancies are important to the magnetic structure and enhance the CEF effects which quench the orbital moment of Ce at low temperatures.