Anisotropic magnetoresistance of CeNiSn

We have measured the magnetoresistance at high fields up to 15 T and at low temperatures down to 0.4 K for CeNiSn with the orthorhombic structure. The longitudinal magnetoresistance (J∥H) is small in magnitude for the magnetic field H∥b- and c-axis. On the other hand, the positive magnetoresistance is found to become dominant with the decrease of temperature for H∥b- and c-axis in the transverse configuration (J⊥H). For H∥a, the magnetoresistance is negative for any current direction. These experimental results have been discussed on the basis of the cyclotron motion of the compensated carriers with closed Fermi surfaces and the reduction of the anisotropic hybridization gap.