Superconductivity in the Mn5Si3-type Zr5Sb3 system.

We report the discovery of superconductivity at 2.3 K in Zr5Sb3, the first superconducting member in the large compound family of the Mn5Si3-type structure. Transport, magnetic, and calorimetric measurements clearly demonstrate bulk superconductivity for Zr5Sb3 and suggest it to be a possible phonon-mediated BCS superconductor with a relatively large density of states at the Fermi level associated with the d electrons of Zr and substantially larger electron-phonon coupling compared to the Sn counterpart compound Zr5Sn3 from band structure calculations. More superconductors with even higher transition temperatures are expected to be found in this family of compounds. [ABSTRACT FROM AUTHOR]