Entropy balance analysis of the AFM-region in the phase diagram of UCu5−Pd

Abstract We present a systematic study of the specific heat in the antiferromagnetic (afm) region of the heavy fermion system UCu5−xPdx for annealed and unannealed samples with x=0.5, 0.6, 0.8, 1.0. Annealed UCu4Pd exhibits a logarithmic temperature dependence of the electronic part of c/T over more than two decades. A careful entropy analysis reveals a nearly constant value of the entropy around 4.0 J mol −1 K −1 for all values of x, which supports the scenario of an afm quantum critical phase (QCP) transition with a vanishing transition temperature TN at x=1.