Thermal expansion of Y0.8U0.2Pd3

Abstract

Abstract We have measured the linear thermal expansion coefficient α ( T ) of polycrystalline Y 1− x U x Pd 3 in the temperature range 0.4–30 K for x =0.2 and from 4.2 to 36 K for x =0.4. For Y 0.8 U 0.2 Pd 3 , α ( T )/ T versus T shows a − ln T dependence between 2 and 14 K, consistent with non-Fermi liquid behaviour related to a two-channel quadrupolar Kondo effect, as previously reported [1,2]. At lower temperatures, the thermal expansion deviates from this temperature dependence, finally becoming negative below T =0.8 K. For Y 0.6 U 0.4 Pd 3 , spin-glass freezing has been reported below T SG ≈ 10 K [1]. Close to this temperature we observe only a deviation of α ( T )/ T from its high temperature behaviour: α ( T ) becomes small in magnitude, changing sign around 5 K, and not showing −ln T dependence. We discuss these experimental results in terms of the two-channel quadrupolar Kondo effect.