2001/08/21 by M. Windt, J. J. McGuire, T. Rõõm +6
Materials Science · Physics and Astronomy · #Iron-based superconductors research #Rare-earth and actinide compounds #Superconductivity in MgB2 and Alloys #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.65.064506
10 pages with 10 embedded figures, submitted to PRB
arxiv created 2001/08/21 · openalex publication_date 2002/01/09 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We present optical conductivity data for Lu(Ni_1\ensuremath-xCox)2B2C over a wide range of frequencies and temperatures for x=0 and 0.09. Both materials show evidence of being good Drude metals with the infrared data in reasonable agreement with dc resistivity measurements at low frequencies. An absorption threshold is seen at approximately 700 cm^\mathrm\ensuremath-1. In the cobalt-doped material, we see a superconducting gap in the conductivity spectrum with an absorption onset at 24\ifmmode±\else\textpm\fi2cm^\ensuremath-1=3.9\ifmmode±\else\textpm\fi0.4kBTc suggestive of weak to moderately strong coupling. The pure material is in the clean limit and no gap can be seen. We discuss the data in terms of the electron-phonon interaction and find that it can be fit below 600 cm^\mathrm\ensuremath-1 with a plasma frequency of 3.3 eV and an electron-phonon coupling constant \ensuremathλtr=0.33 using an \ensuremathα2F(\ensuremathω) spectrum fit to the resistivity.