Crossover from non-Fermi-liquid to Fermi-liquid behavior in the magnetoresistivity of U0.9Th0.1Be13

We have measured the temperature T and magnetic field H dependence of the electrical resistivity ρ of U0.9Th0.1Be13 in the ranges 0.08 K≤T≤10 K and 0 kOe≤H≤80 kOe. In zero applied magnetic field below 0.7 K, the resistivity displays a linear temperature dependence, characteristic of non-Fermi-liquid behavior, down to 0.23 K, where it then saturates as T2, consistent with Fermi-liquid behavior, down to 0.08 K, the lowest temperature attained in the experiment. Magnetic fields up to 40 kOe have practically no effect on the electrical resistivity above 1 K, but dramatically influence the low temperature ρ(T) behavior below 0.7 K. At temperatures below 0.7 K, an anomalously large positive magnetoresistivity is accompanied by a rapid expansion of the temperature region where Fermi-liquid behavior is observed. copyright 1997 The American Physical Society