CRYSTAL-GROWTH AND CHARACTERIZATION OF THE KONDO SEMIMETAL CENISN

Several single crystals of CeNiSn and CeNi0.95T0.05 Sn (T = Co and Cu) were grown and characterized by metallographic examination, electron- probe microanalysis and the measurements of resistivity, magnetoresist ance, magnetic susceptibility and specific heat. Below 10 K, the semic onductor-like behavior found for dirty or substituted crystals is supp ressed with decreasing impurities. For a crystal purified by the solid -state electrotransport technique, the resistivity along the orthorhom bic a axis is metallic with the T-2 dependence, whereas those along th e b and c axes increase below 3 K and pass through weak maxima at 0.8 K. These results suggest that the ground state of CeNiSn is not semico nducting but semimetallic with a pseudogap which closes along the a ax is.