Effects of ordered structure on superconductivity in Ti 70-xZr 30Nb x (15≤ x ≤ 60)

Superconductivity and structural properties of Ti70-xZr30Nbx have been systematically investigated for x ranging from 0 to 60. Superconductivity is observed in the cubic beta-phase with 10 <= x <= 60. Moreover, evident modifications in superconductivity and superstructure, being interpreted as Nb and Ti local orders, are discovered in samples with 25 <= x <= 50. This superstructure phase in general coexists with the cubic beta-phase and yields two superconducting transitions in the superconducting materials. Electronic structure calculations reveal a relatively higher density of states for the superstructure phase at the Fermi level, therefore a strong electron-phonon coupling and higher superconducting T-c are expected in agreement with the experimental data. Copyright (C) EPLA, 2012