We measured the resistivity, diamagnetization and low temperature specific heat of the newly discovered noncentrosymmetric superconductor $Mg_{ 10}Ir_{ 19}B_{ 16}$. It is found that the superconducting gap has an s-wave symmetry with a value of about $\Delta_0 \approx$ 0.6 meV, and the ratio $\Delta_0/k_BT_c\approx1.86$ indicates a weak coupling for the superconductivity. The correlations among the normal state Sommerfeld constant $\gamma_n$, the slope $-d\mu_0H_{ c2}(T)/dT$ near Tc and the condensation energy Ec are all consistent with the weak coupling picture. The separated phonon contribution from the specific heat shows that the conduction electrons of the $Ir$ atoms interact most strongly with the vibrations of themselves, instead of with that of the light element boron.
Categories: cond-mat.supr-con