Magnetic and thermal properties of Ferromagnetic (FM)
Ce_{2.15}(Pd_{1-x}Ag_x)_{1.95}In_{0.9} alloys were studied in order to
determine the Quantum Critical Point (QCP) at T_C => 0. The increase of band
electrons produced by Pd/Ag substitution depresses T_C(x) from 4.1K down to
T_C(x=0.5)=1.1K, with a QCP extrapolated to x_{QCP}~ 0.6. Magnetic
susceptibility from T>30K indicates an effective moment slightly decreasing
from \mu_{eff}=2.56\mu_B to 2.4\mu_B at x=0.5. These values and the
paramagnetic temperature \theta_P~ -10K exclude significant Kondo screening
effects. The T_C(x) reduction is accompanied by a weakening of the FM
magnetization and the emergence of a specific heat C_m(T) anomaly at T*~ 1K,
without signs of magnetism detected from AC-susceptibility. The magnetic
entropy collected around 4K (i.e. the T_C of the x=0 sample) practically does
not change with Ag concentration: S_m(4K)~ 0.8 Rln2, suggesting a progressive
transfer of FM degrees of freedom to the non-magnetic (NM) component. No
antecedent was found concerning any NM anomaly emerging from a FM system at
such temperature. The origin of this anomaly is attributed to an 'entropy
bottleneck' originated in the nearly divergent power law dependence for T>T*.Comment: 5 pages, 4 figures, Int. Conf. ICM 201
