Superconductivity and structural transformation in V₂Hf-based C15 pseudobinary compounds

Abstract

Superconductivity and structural transformation have been studied through resistivity measurements on V2Hf-based pseudobinary compounds V2(Hf1-xMx) (M=Y, Ti, Nb and Ta). Both the superconducting transition temperature Tc and the structural transformation temperature TL depend strongly on the electron-atom ratio e/a. There is a correlation between TL and the electron-phonon coupling parameter lambda derived from the experimental value of Tc, which suggests that superconductivity is strongly related to lattice instabilities. The value of Tc of 10.7K obtained for V2(Hf0.84Nb0.16) is the highest reported so far for a compound with C15 structure.