CeCu2Si2 and UBe13: New questions - Old answers?

Non-Fermi-liquid (Nn) temperature dependences of both the resistivity rho(T ) and the Sommerfeld coefficient gamma(T) are observed for normal-state CeC u2Si2 and UBe13. For the former compound, the NFL effects are related to th e suppression (via pressure or suitable composition) of the spin-density-wa ve (SDW)-type 'phase A' (T-A --> 0) Upon approaching the quantum critical p oint, rho(T) and gamma(T) behave very disparately, indicating a decoupling of the itinerant and local 4f parts of the heavy-fermion quasiparticles. Si milar observations are made with UBe13 for which, however, no magnetic phas e transition could so far be established. New anomalies are discovered in s uperconducting U1-xThxBe13 with 0 less than or equal to x < x(cr) = 0.019. (C) 1998 Elsevier Science Ltd. All rights reserved.