  We report the thermodynamic, magnetic, and electronic transport properties of
the new ternary intermetallic system (Ce,La)3Pt4In13. Ce3Pt4In13 orders
antiferromagnetically at 0.95 K while the non-magnetic compound La3Pt4In13 is a
conventional 3.3 K superconductor. Kondo lattice effects appear to limit the
entropy associated with the Neel transition to (1/4)Rln2 as an electronic
contribution to the specific heat of gamma = 1 J/mole-Ce K2 is observed at TN;
roughly 35% of this gamma survives the ordering transition. Hall effect,
thermoelectric power, and ambient-pressure resistivity measurements confirm
this interpretation. These results suggest that RKKY and Kondo interactions are
closely balanced in this compound (TN = TK). Contrary to expectations based on
the Doniach Kondo necklace model, applied hydrostatic pressure modestly
enhances the magnetic ordering temperature with dTN/dP = +23 mK/kbar. As such
Ce3Pt4In13 provides a counterexample to Kondo systems with similar Kondo and
RKKY energy scales wherein applied pressure enhances TK at the expense of the
ordered magnetic state.
