Superconducting transition parameters in aluminum–lithium alloys (0–10 at.% Li)
M.N. Oua, b, T.J. Yanga, B.J. Chenb, Y.Y. Chenb and J.C. Hoc, ,
aDepartment of Electrophysics, National Chiao Tung University, Hsinchu, Taiwan bInstitute of Physics, Academia Sinica, Taipei, Taiwan cDepartment of Physics, Wichita State University, Wichita, KS, USA Received 12 March 2007; accepted 25 March 2007. by A.H. MacDonald. Available online 31 March 2007.
The superconducting transition temperatures Tc of face-centered cubic Al1−x–Lix alloys (x=0–0.10) exhibit a minimum near x=0.03 (3 at.% Li). The McMillan strong-coupling Tc equation yields a similar trend of the electron–phonon coupling constant λ. Meanwhile, the density of states at the Fermi level N(0) decreases monotonically with increasing x. It appears that Tc drops initially due to a reduced N(0), which is then overtaken by alloying-enhanced factors of phonon or electron–phonon interaction.
Keywords: A. Superconductors; D. Electron–phonon interactions