THERMAL-CONDUCTIVITY OF SINGLE-CRYSTALLINE CERU2SI2

The thermal conductivity kappa and the electrical resistivity rho of s ingle-crystalline CeRu2Si2 were measured in the temperature region bet ween 1.7 and 80 K in magnetic fields up to 15 T. A reduced Lorentz num ber L/L-0 shows a peak at H-M where a metamagneticlike transition take s place even at low temperatures where L/L-0 is smaller than 1 as a wh ole. This indicates a smaller inelastic scattering effect at H-M than below and above H-M. For H=0, a clear enhancement of kappa is observed below the crossover temperature Tsimilar to 10 K. However, it is rap idly smeared out by the magnetic field and is completely suppressed at H-M. Above H-M, a pronounced enhancement of kappa and a clear decreas e of rho are observed below the characteristic crossover temperature T *, which is due to a significant decrease of magnetic scattering of c onduction electrons.