Enhancement of critical temperature and upper critical field due to Nb substitution in Zr-V alloy superconductors

摘要

We report here the structural, electrical and magnetic properties of the annealed Nb_xZr_(1-x)V_2 alloys. We have observed that all the alloys formed mainly in a face centred cubic γ-ZrV_2 phase with small amount of β-V phase. The addition of Nb to ZrV2 increases the superconducting critical temperature (TC) from 8.4 K for x = 0 to 9.46 K for x = 0.2. It is also observed that the upper critical field (H_(C2)(0)) in the zero temperature limit increases from about 14T for x = 0 to 26.4 T for x = 0.2. Further increase in x results in the decrease of both TC and H_(C2)(0). Moreover, the martensitic transformation observed in ZrV_2 is absent in the Nb substituted alloys.