ANOMALOUS SCATTERING OF QUASI-PARTICLES BY CO AND CU IMPURITIES IN THE KONDO SEMIMETAL CENISN

We present results of the magnetic susceptibility chi(T), electrical r esistivity rho(T) and Hall coefficient R-H(T) for CeNi1-xTxSn (T = Co and Cu, 0 less than or equal to x less than or equal to 0.05). Co impu rities decrease chi along all the principal axes, whereas Cu impuritie s increase. Both impurities at x = 0.01 cause a remarkable increase in rho at 1.4 K with 970 mu Omega cm/at% Cu at maximum. For x = 0.05, rh o(T) is saturated to a lower value than that for x = 0.01. R-H(T) for x = 0.01 Co and Cu becomes negative below about 4 K and the absolute v alue is smaller than that for x = 0, while R-H for x = 0.05 remains po sitive down to 1.6 K. The nonmonotonic dependence of rho(T) and R-H(T) on x indicates extremely strong scattering of quasiparticles from non magnetic impurities in the presence of pseudogap.