Magnetotransport of (formula presented)

We report measurements of the temperature-dependent anisotropic resistivity and in-plane magnetoresistance on single crystals of the tetragonal heavy-fermion antiferromagnet (formula presented) (formula presented) The measurements are reported in the temperature range 1.4-300 K and in magnetic fields to 18 T. The resistivity is moderately anisotropic, with a room-temperature c-axis to in-plane resistivity ratio (formula presented)(formula presented) measurements on the nonmagnetic analog (formula presented) indicate that the anisotropy in the (formula presented) resistivity stems predominantly from anisotropy in Kondo-derived magnetic scattering. In the magnetically ordered regime, an applied field H reduces (formula presented) only slightly due to the small ordered moment (formula presented) and magnetic anisotropy. The magnetoresistance (MR) below (formula presented) is positive and shows little sign of saturating in fields to 18 T. In the paramagnetic state, a positive MR is present below 7.5 K, while a high-field negative contribution is evident at higher temperatures. The positive contribution decreases in magnitude with increasing temperature. Above 40 K the positive contribution is no longer observable, and the MR is negative. The low-T positive MR results from interactions with the Kondo-coherent state, while the high-T negative MR stems from single-impurity effects. In general, these results indicate that (formula presented) exhibits a modest degree of transport anisotropy not atypical among heavy-fermion compounds.