Magnetotransport in the heavy-fermion system YbNi2B2C

We have measured the high field transverse magnetoresistance and magnetizat ion on single crystalline samples of YbNi2B2C with the applied magnetic fie ld both parallel and perpendicular to the c axis of the tetragonal crystal structure. At high temperatures, the magnetoresistance is negative with a m agnitude that increases as the temperature is lowered. A scaling analysis o f the data for H perpendicular to c finds a characteristic energy that is s imilar to 20 K at low temperatures, which is a factor of 2 larger than the Kondo temperature determined from thermodynamic measurements, and it increa ses linearly with the temperature. Even though the magnetoresistance for H parallel to c is also negative, the data do not scale. At low temperatures, the magnetoresistance is very anisotropic. In the Fermi-liquid regime belo w similar to 1.6 K, the resistivity has a temperature-independent contribut ion due to ligand and/or Kondo-hole disorder and a term from electron-elect ron scattering that goes like T-2. For H perpendicular to c, the residual r esistivity and the T-2 coefficient are field dependent. Both the high- and low-temperature data are compared to various theoretical calculations. [S01 63-1829(99)14631-9].