2004/07/31 by R. S. Gonnelli, D. Daghero, Arrigo Calzolari +11 · 72 citations
Materials Science · Physics and Astronomy · #Computer science #Condensed matter physics #Iron-based superconductors research #Physics #Superconductivity #Superconductivity in MgB2 and Alloys #Thermal Expansion and Ionic Conductivity #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.71.060503
published in Physical Review B 71(6) (American Physical Society) · 5 pages, 5 figures. One figure and one panel added; text and discussion updated
arxiv created 2004/09/24 · openalex publication_date 2005/02/14 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We report the results of the first directional point-contact measurements in Mg(B_1\ensuremath-xCx)2 single crystals with 0.047\ensuremath\leqslantx\ensuremath\leqslant0.132. The two-gap superconductivity typical of MgB2 persists up to x=0.105. In this region, the values of the gaps \ensuremathΔ_\ensuremathσ and \ensuremathΔ_\ensuremathπ were determined by fitting the Andreev-reflection conductance curves with a two-band Blonder-Tinkham-Klapwijk (BTK) model, and confirmed by the single-band BTK fit of the \ensuremathσ- and \ensuremathπ-band conductances, separated by means of a magnetic field. At x=0.132, when Tc=19\phantom\rule0.3em0exK, we clearly observed the merging of the two gaps into one of amplitude \ensuremathΔ\ensuremath≃3\phantom\rule0.3em0exmeV.