Thermal and Transport properties of U$_{2}$Pt$_{1-x}$Ir$_{x}$C$_{2}$

We report thermal and transport properties of U$_{2}$Pt$_{1-x}$Ir$_{x}$C$_{2}$ from which a magnetic phase diagram is obtained. Pure U$_{2}$IrC$_{2}$ is an antiferromagnet at 6.5 $K$, whose Neel temperature initially rises to 13.2 $K$ at $x$=0.8 and subsequently is suppressed to zero temperature with increasing Pt content near $x$=0.4. Heat capacity data at $x$=0.4 shows an upturn at low temperature, which is consistent with proximity to a quantum critical point and considered as non-Fermi liquid behavior. The entropy after the phonon contribution has been subtracted has a value of 0.18 $Rln2$ at the Neel temperature of U$_{2}$IrC$_{2}$, revealing an itinerant nature of the 5f electrons in this compound. On the Pt rich side of the phase diagram, superconductivity is suppressed by $x$=0.15. The residual resistivity increases by a factor of 10 from pure Pt ($x$=0) to $x$=0.15 where superconductivity is suppressed to zero. The phase diagram is compared to pressure tuned and Rh doped U$_{2}$PtC$_{2}$ demonstrating the role of electronic tuning in this system.