Anisotropic magnetoresistance in UBe13

Angular dependence of the transverse magnetoresistance of a heavy-fermion superconductor UBe13 (Tc=0.9 K) was measured on a single crystal grown by the Al-flux method. The resistivity decreases with increasing the magnetic field at low temperatures, indicating that a magnetic scattering is suppressed by the magnetic field. We observed a remarkable angular dependence in magnetoresistance at 0.45 K under a constant field of 13 T, showing a minimum at the [1 1 0] direction. This anisotropy of magnetoresistance is observed below 4 K. Since the large resistivity (200 μΩ cm) of this compound at low temperatures is attributed to the magnetic scattering by uranium ions, the present anisotropy in the magnetic scattering at low temperatures would give important information about the ground state of 5f electrons.