Superconducting properties of the ternary transition-metal silicide Zr 2 Ru 3 Si 4

Superconducting properties of the polycrystalline Zr2Ru3Si4 were investigated by the electrical resistivity, magnetization and specific heat. By these measurements, bulk superconductivity with transition temperature Tc = 5.5 K was confirmed. Moreover, Zr2Ru3Si4 was found to be a type-II and intermediate-coupling superconductor. Interestingly, the electronic specific heat shows a deviation from a one-gap s-wave model and Hc2(T) shows unusual positive curvature in the vicinity of Tc. The first principle's calculation shows the existence of plural anisotropic Fermi surfaces. These results suggest that Zr2Ru3Si4 is not an isotropic single-gap superconductor, but possibly a multi-gap or an anisotropic gap superconductor.