We report the discovery of superconductivity at 2.3 K in Zr${}_5$Sb${}_3$, the first superconducting member in the large compound family of the Mn${}_5$Si${}_3$-type structure. Transport, magnetic, and calorimetric measurements clearly demonstrate bulk superconductivity for Zr${}_5$Sb${}_3$ 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 Zr${}_5$Sn${}_3$ from band structure calculations. More superconductors with even higher transition temperatures are expected to be found in this family of compounds.

• Received 24 September 2013

DOI:https://doi.org/10.1103/PhysRevB.88.134520