Possible quadrupolar ordering in a Kondo-lattice compound Ce3Pd20Ge6.

Magnetic and transport properties of the cubic ternary compound ${\mathrm{Ce}}_{3}$${\mathrm{Pd}}_{20}$${\mathrm{Ge}}_{6}$ are herein reported. The electrical resistivity exhibits the Kondo lattice behavior and a large ${T}^{2}$ coefficient at low temperatures, indicating that this compound is a heavy-electron system with a Kondo temperature of a few degrees Kelvin. The low-temperature specific heat revealed two successive anomalies at ${T}_{1}=1.2$ K and ${T}_{2}=0.7$ K. The ${\ensuremath{\Gamma}}_{8}$ quartet crystalline-field ground state of Ce ions is conjectured from the thermal variation of magnetic entropy deduced from the specific-heat data. The anomaly at ${T}_{1}$ is probably a result of quadrupolar interaction between ${\ensuremath{\Gamma}}_{8}$ ground states, while the other one at ${T}_{2}$ is due to antiferromagnetic ordering.