Magnetic order and crystal-field excitations in Nd3Pd20Ge6

The magnetic properties of the new cubic intermetallic compound Nd3Pd20Ge6 have been investigated by neutron scattering and low-temperature specific heat experiments. The results include the refinement of the crystal structure at 10 K (space group Fm (3) over bar m, No 225), the observation of three successive magnetic phase transitions (at T-N1 = 1.75 K, T-N2 = 1.40 K and T-N3 = 0.54 K), the determination of the antiferromagnetic structure between T-N1 and T-N2 (antiferromagnetically ordered Nd moments on site 8c coexist with disordered Nd moments on site 4a) and the measurement of the crystalline-electric-field (CEF) level scheme (Gamma(8)((1))) --> Gamma(6) --> Gamma(8)((2))) in the paramagnetic state. An extrapolation of the CEF parameters obtained for Nd3Pd20Ge6 predicts the CEF ground-states to be the tripler Gamma(5) in Pr3Pd20Ge6 and the quarter Gamma(8) in Ce3Pd20Ge6.