A new heavy-fermion superconductor

$\ab{CeIrIn_5}$ is a member of a new family of heavy-fermion compounds and has a Sommerfeld specific-heat coefficient of $720\un{mJ/mol K^2}$. It exhibits a bulk, thermodynamic transition to a superconducting state at $T_{\ab c}=0.40\un{K}$, below which the specific heat decreases as T2 to a small residual T-linear value. Surprisingly, the electrical resistivity drops below instrumental resolution at a much higher temperature $T_0=1.2\un{K}$. These behaviors are highly reproducible and field-dependent studies indicate that T0 and $T_{\ab c}$ arise from the same underlying electronic structure. The layered crystal structure of $\ab{CeIrIn_5}$ suggests a possible analogy to the cuprates in which spin/charge pair correlations develop well above $T_{\ab c}$