Possible quadrupolar ordering in a Kondo-lattice compound ${\mathrm{Ce}}_3$${\mathrm{Pd}}_{20}$${\mathrm{Ge}}_6$

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 $T_1=1.2\mathrm{}$ K and $T_2=0.7\mathrm{}$ K. The ${\Gamma }_8$ 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 ${\Gamma }_8$ ground states, while the other one at $T_2$ is due to antiferromagnetic ordering.