[en] Thermal conductivity has been measured from 0.03 K to 0.8 K in single crystal CeNi₂Ge₂ which is quite near the quantum critical point (QCP). The Wiedemann-Franz law is observed at low temperatures (T < 0.1 K) for both directions (j perpendicular c and j parallel c), indicating that quasiparticles are scattered elastically as T r_arrow 0 K. With increasing temperature, a deviation from the Wiedemann-Franz law due to inelastic spin-fluctuation contributions is observed. The effect of proximity to the QCP in CeNi₂Ge₂ appears in the spin-fluctuation contributions to the thermal and electrical conductivities

[en] [³H]DL-Valine, [³H]DL-leucine and [³H]DL-methionine were resolved using ligand-exchange chromatography (reverse-phase) in the presence of cupric acetate [Cu(II)], and 5'-guanozine monophosphate or cyanocobalamin. The assignment of the resolved enantiomers was carried out by means of co-chromatography with non-labeled DL-amino acids after modifying them with fluorodinitrobenzene. The optical purity of the enantiomers was estimated to be greater than 99%. The resolved enantiomers were subjected to bioassay, which showed that the enantiomers were biochemically active. (author)

[en] Previously, an analogy has been observed between the application of hydrostatic and chemical pressure on the properties of CeRu₂(Ge,Si)₂ alloys. In order to test this analogy on a microscopic scale we examined the magnetic pressure phase diagram of single-crystalline CeRu₂Ge₂ and CeRu₂(Ge_0.7Si_0.3)₂ by means of elastic neutron scattering. The results from our microscopic study of the p-x-T phase diagram of CeRu₂(Ge,Si)₂ are in full agreement with those previously determined by means of bulk experiments

[en] Specific heat up to 200 K from below 1 K for Ce(Ni/Pd)₂Ge₂ single crystals is presented. The magnetic part of the specific heat for CeNi₂Ge₂ forms two broad peaks around 30 and 150 K. The crystal field excitation with Δ₁=200∼280 K and Δ₂=300∼380 K is roughly estimated from analysis on the entropy balance under Kondo state with T_K=30 K. Substitution of Ni-site by Pd makes T_K to reduce and a non-Fermi-liquid characteristics to change into an usual Kondo-type behavior with magnetic ordering at low temperatures beyond 10% substitution

[en] [¹⁴C]DL-Tryptophan, [¹⁴C]DL-phenylalanine and [³⁵S]DL-methionine were resolved using cellulose column chromatography. The assignment for the resolved enantiomers was carried out by means of co-chromatography with non-labeled DL-amino acids after modification with fluorodinitrobenzene. The optical purity of the enantiomers was estimated to be greater than 99%. The resolved enantiomers were provided for bioassay, showing that the enantiomer was biochemically active. (author)

[en] Neutron scattering shows that non-Fermi-liquid behavior of the heavy-Fermion compound CeNi₂Ge₂ is brought about by development of low-energy spin fluctuations with an energy scale of 0.6 meV. They appear around antiferromagnetic wave vectors (1/2 1/2 0) and (0 0 3/4) at low temperatures, and coexist with high-energy spin fluctuations with an energy scale of 4 meV and a modulation vector (0.23, 0.23, 1/2). The energy dependence of the spin fluctuations is a peculiar character of CeNi₂Ge₂ which differs from typical heavy-Fermion compounds, and suggests importance of low-energy structures of quasiparticle bands. (author)

[en] The specific heat (C) and Hall coefficient (R_H) in CeNi₂Ge₂ single crystals have been investigated for the field (B) along the c- and a-axis. At B = 0, C/T varies approximately as T^1/2 down to 0.2 K, suggesting non-Fermi-liquid behavior. On application of B, we found a recovery of Fermi-liquid behavior in C, which is only weakly anisotropic. In contrast, the temperature dependence of R_H is anisotropic; the sign is negative for B parallel c and positive for B parallel a below 300 K. (orig.)

[en] The electrical resistivity and the lattice parameters of the tetragonal heavy-fermion compound CeNi₂Ge₂ with ThCr₂Si₂ type of structure have been investigated under high pressure. At room temperatures, the compression curve of an unit-cell volume up to 70 kbar is well fitted to Murnaghan equation of state. In the electrical resistivity at low temperatures, a gradual depression of the Fermi-liquid AT² term with increasing pressure is observed. From these results, the Grueneisen parameter of the characteristic energy of the Fermi-liquid ground state is determined to be 90. (orig.)

[en] The antiferromagnetic correlations in the non-Fermi-liquid compound CeNi₂Ge₂ have been measured on single crystals using inelastic neutron scattering. The spin fluctuations with a characteristic energy of 4 meV are centred at the incommensurate wave vector (0.23, 0.23, 0.5), which is similar to where magnetic order develops in the related compound CeCu₂Ge₂. The magnetic correlations are anisotropic, with a quasi-two-dimensional extension along the [110] direction, implying that the moments are mostly correlated in the [110] planes. With increasing temperature, the correlated signal decreases, and above T* approx. 30 K the magnetic scattering appears to be wave-vector independent. (author)

[en] The specific heats of Ce₃Ir₄Sn₁₃ have been measured between 30 mK and 70 K in magnetic fields up to 4 T. We observed the two main specific heat peaks at 0.6 K and at 2.1 K, which is resolved well into two successive peaks. A magnetic field versus temperature phase diagram is presented. ((orig.))