Thermal-transport properties of CeNiSn

We present thermal-conductivity K and thermopower S measurements on high-qu ality single crystalline CeNiSn along the three crystallographic axes a, b, and c in thr temperature range between 100 mK and 7 K and in magnetic fiel ds up to 8 T applied along the a axis. Both K and S are highly anisotropic. However, characteristic features that may be attributed to the opening of a pseudogap in the electronic density of states (DOS) at the Fermi energy e ta below 10 K are seen for all three crystallographic directions. These fea tures are strongly suppressed by a magnetic field of 8 T applied along the a axis. At the lowest temperatures we have evidence for the presence of a r esidual metallic DOS at eta, again for all three directions. The saturation of the reduced Lorenz number L/L-0 to a value distinctly higher than one i s an interesting feature which deserves further investigation.