AC heat capacity and resistivity measurements on the pressure-induced superconductor CeIrSi3 without inversion center

Abstract We present the result of an antiferromagnet CeIrSi 3 without inversion center by measuring the heat capacity and the electrical resistivity of CeIrSi 3 . Both physical quantities were measured in the same run for the same single crystal sample. A huge heat capacity anomaly was observed at the superconducting transition temperature T sc = 1.6 K where the zero-resistivity was observed. The jump of the heat capacity Δ C ac / C ac is 5.7 ± 0.1 at 2.58 GPa. This value is the largest among previously reported superconducting materials, indicating the strong coupling superconductivity. The electronic specific heat coefficient just above T sc is roughly estimated to be 100 ± 20 mJ / K 2 mol at 2.58 GPa, which is the same as γ = 120 ± 20 mJ / K 2 mol at ambient pressure.