Effect of Kondo-hole impurity on the pseudogap in CeNiSn

Electrical resistivity ρ , Hall coefficient R H and magnetic susceptibility χ , are reported on single crystals of Ce 1− y La y NiSn ( y =0, 0.01 and 0.05). The negative increase in R H for y =0 on cooling below 4 K is weakened for y =0.01, whereas R H for y =0.05 remains positive down to 1.4 K. At this temperature, both ρ b and ρ c for y =0.01 are about five times larger than that for y =0, while those for y =0.05 saturate to values smaller than those for y =0.01. Furthermore, the maximum in χ a at 13 K disappears for y =0.05. The close resemblance of these results to those found in CeNi 1− x Co x Sn indicates that irrespective of the 4f-site and the non-4f site the Kondo-hole imputity strongly scatters the carriers remaining in the pseudogap.