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 b y 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 charac teristic temperatures, derived from this scaling, are 2 and 2.5 K. The heav y fermion character of both compounds was confirmed by large values of the electronic specific-heat coefficients in the ordered states. C/T extrapolat ed 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 fer romagnetic correlations. These ferromagnetic correlations are consistent wi th the previously reported magnetization and magnetic susceptibility. C/T i s sublinear in T-2 below 1 K and extrapolated to 0 K is only of order 100 m J/K-2 mel.