Superconducting properties and electronic structure of CuAl2-type transition-metal zirconide Fe1-Ni Zr2

CuAl 2 -type transition-metal ( Tr ) zirconides are a superconductor family, and the Tr -site element substitution largely modifies its transition temperature ( T c ). Here, we synthesized polycrystalline samples of Fe 1- x Ni x Zr 2 by arc melting. The crystal structure and the superconducting properties were studied through synchrotron X-ray diffraction, magnetic susceptibility, electrical resistivity, and specific heat measurements. Bulk superconductivity was observed for 0.4 ≤ x ≤ 0.8, and the highest T c of 2.8 K was observed for x = 0.6. The obtained superconductivity phase diagram exhibits a dome-shaped trend, which is similar to unconventional superconductors, where magnetic fluctuations are essential for superconductivity. In addition, from the c / a lattice constant ratio analysis, we show the possible relationship between the suppression of bulk superconductivity in the Ni-rich compositions and a collapsed tetragonal transition. • New superconducting samples of Fe 1- x Ni x Zr 2 were discovered. • The superconductivity phase diagram exhibits a dome shape, and the end members are not bulk superconductors; the trend is similar to unconventional spin-related superconductors. • Using synchrotron X-ray diffraction and various probes including specific heat, bulk nature of the target phases have been confirmed.