Magnetoresistance and low-temperature specific heat of the Yb compounds YbRhSn, YbPdBi, and YbPtSn

The antiferromagnetic compounds YbPtSn, YbRhSn, and YbPdBi were studied by specific heat down to 0.35 K. Their paramagnetic states were investigated by magnetoresistance at temperatures between 4 and 50 K and in fields up to 8 T. The magnetoresistance of YbRhSn and YbPdBi exhibits a single impurity Kondo scaling at all temperatures studied. The respective single-ion characteristic temperatures, derived from this scaling, are 2 and 2.5 K. The heavy fermion character of both compounds was confirmed by large values of the electronic specific-heat coefficients in the ordered states. C/T extrapolated to T=0 is 1200+/-200 mJ/K-2 mol for YbRhSn and 1200+/-100 mJ/K-2 mol for YbPdBi. The magnetoresistance of YbPtSn implies the presence of strong ferromagnetic correlations. These ferromagnetic correlations are consistent with the previously reported magnetization and magnetic susceptibility. C/T is sublinear in T-2 below 1 K and extrapolated to 0 K is only of order 100 mJ/K-2 mel.