Deviation from Kohler’s Rule Closely Correlated with the Field-Insensitive −log T Dependence of Resistivity in SmTa2Al20

We have performed electronic transport measurements of single-crystal SmTa2Al20 to investigate its characteristic features of conduction electron scattering relevant to the field-insensitive −log T dependence of resistivity. The transverse magnetoresistance (MR) is always positive with H2 dependence over the investigated temperature range, indicating that MR due to the cyclotron motion of conduction electrons far exceeds the expected suppression of the Kondo scattering by a magnetic field. We found a strongly enhanced deviation from Kohler’s rule in MR in the low-field condition, which indicates that the conduction electron scattering by 4f electrons has a strong wave-vector dependence. We also found that the modified Kohler’s rule, which has been confirmed in some of the strongly correlated electron systems with quasi-two-dimensional crystal structures, holds in SmTa2Al20, providing the first example of a cubic three-dimensional system.