抄録
Specific heat C, electrical resistivity ρ, magnetization M and magnetic susceptibility χ have been measured for the dilute tetragonal heavy-electron compounds UxTh1-xRu2Si2 (x≤ 0.07), in the temperature range 100, mK≤ T≤ 360, K and in the magnetic fields H up to 55, kOe. Non-Fermi-liquid behavior with unusual lnT dependence of C, ρ and χ has been observed at the low temperatures: as the temperature is lowered below about 10, K, C/T and χ increase logarithmically, and ρ decreases logarithmically. Systematical variations of these quantities with uranium concentration indicate that the observed non-Fermi-liquid behavior is ascribed to the properties of a single U ion embedded in the Th site of the ThRu2Si2 metal. The magnetization curves M vs H/T indicate a strong uniaxial magnetic anisotropy along the tetragonal c-axis as well as a strong reduction of the 5f moment of U ions. A possible interpretation based on the recent developments of the S=1/2 two-channel Kondo model is given.
