Superconductivity in the intermetallic compound Zr5Al4

Abstract

Polycrystalline compound Zr5 Al4 was synthesized using the arc-melting method. Powder x-ray diffraction confirms previously reported crystal structure of Ti5 Ga4 -type (P63 /mcm) with lattice parameters: a =8.4312(6) Å, and c = 5.7752(8) Å. The electrical resistivity and low temperature magnetic susceptibility studies indicate that Zr 5 Al4 exhibits superconducting behavior. The normalized heat capacity jump at Tc = 1.82 K is ΔC/γT c = 1.41 and confirms bulk superconductivity. The Sommerfeld coefficient γ = 29.4 mJ mol-1 K -2 and the Debye temperature D = 367 K were obtained by fitting the low temperature heat capacity data. The electron-phonon coupling strength λ el-ph = 0.48 and estimated upper critical field μ0 H c2 (0) = 1.09 T (dirty limit) suggest that Zr5 Al4 is a weakly coupling type-II superconductor. The first- principles calculations show presence of the van Hove singularity near the Fermi that plays the significant role in the superconductivity.