Thermal-Expansion And Infrared Optical-Properties Of Heavy-Fermion Cenisn

Thermal expansion alpha (0.5 < T < 50) K properties and infrared (IR) optical spectra (4.2 < T < 310) K of CeNiSn - a new heavy-fermion compound with a small gap at Fermi level - are presented. Our data strogly suggest the absence of a magnetic transition down to 2 K. At lower temperatures a peak near 1.3 K in the alpha/T temperature dependence and a change of sign of alpha-below 1 K was observed. These features possibly indicate the appearance of magnetic correlations below 1 K.