Superconductivity and structural transformation in V2Hf-based C15 pseudobinary compounds

Superconductivity and structural transformation have been studied through resistivity measurements on V2Hf-based pseudobinary compounds V2(Hfsub(1-x)Msub(x)) (M=Y, Ti, Nb and Ta). Both the superconducting transition temperature Tsub(c) and the structural transformation temperature Tsub(L) depend strongly on the electron-atom ratio e/a. There is a correlation between Tsub(L) and the electron-phonon coupling parameter lambda derived from the experimental value of Tsub(c), which suggests that superconductivity is strongly related to lattice instabilities. The value of Tsub(c) of 10.7 K obtained for V2(Hfsub(0.84)Nbsub(0.16)) is the highest reported so far for a compound with C15 structure. (author)