Unconventional − Log T Dependent Resistivity in SmxLa1−xTa2Al20

We have succeeded in growing SmxLa1-xTa2Al20 single-crystals, and performed electronic transport measurements to investigate the characteristic features of conduction electron scattering relevant to the field-insensitive – logT dependence of the resistivity. We have found that the – logT dependence of the resistivity remains in a Sm-dilute compound with x = 0.01. This finding provides clear evidence for that the – logT dependence is caused by a local single-ion Kondo effect. We have measured magnetoresistance (MR) of SmTa2Al20 up to 14 T and confirmed that the positive MR continues to develop with decreasing temperature even at 0.5K, evidencing a large deviation from Kohler's rule. This fact indicates that strong wave-vector dependence of conduction-electron scattering by 4f electrons still remains at 0.5K in the magnetically ordered state.