  We present here the results of electrical resistivity {\rho}, magnetization
M, ac susceptibility \c{hi}ac', and specific heat CM measurements that have
been carried out on single crystals of Yb3Pt4 over a wide range of fields and
temperatures. The 2.4-K N\'eel temperature that is found in zero field
collapses under field to a first-order transition TN=0 at BCEP=1.85 T. In the
absence of antiferromagnetic order, the specific heat CM(T,B), the
magnetization M(T,B), and even the resistivity {\rho}(T,B) all display B/T
scaling, indicating that they are dominated by strong paramagnetic
fluctuations, where the only characteristic energy scale results from the
Zeeman splitting of an energetically isolated, Yb doublet ground state. This
paramagnetic scattering disappears with the onset of antiferromagnetic order,
revealing Fermi liquid behavior {\Delta}{\rho}=AT2 that persists up to the
antiferromagnetic phase line TN(B), but not beyond. The first-order character
of TN=0 and the ubiquity of the paramagnetic fluctuations imply that
non-Fermi-liquid behaviors are absent in Yb3Pt4. In contrast to heavy fermions
such as YbRh2Si2, Yb3Pt4 represents an extremely simple regime of f-electron
behavior where the Yb moments and conduction electrons are almost decoupled,
and where Kondo physics plays little role.
