Third-order magnetic susceptibility and quadrupolar order parameter of Kondo-lattice compound Ce3Pd20Ge6

We present a report on crystalline-electric-field effects observed in the e lectrical resistivity and the specific heat of Ce3Pd20Ge6, which are discus sed within an energy level scheme of the Gamma(8) ground state and the Gamm a(7) excited state at 50 K for both inequivalent crystallographic sites of Ce atom. The third-order magnetic susceptibility was deduced from the magne tization measurement in the paramagnetic phase of a single-crystalline samp le in magnetic fields applied along [0 0 1] and [1 1 1]. In order to explai n the temperature dependence of the third-order magnetic susceptibility alo ng [0 0 1], a positive total quadrupolar pair interaction constant of 22 mK is required in addition to a small antiferromagnetic exchange interaction, thereby suggesting ferroquadrupolar ordering with the Gamma(3) symmetry in this compound.