Distribution of the superconducting gap in an YNi2B2C film studied by point contact spectroscopy

Abstract

The differential resistances $R_d=dV/dI(V)$ of point contacts between a normal metal and a c axis oriented YNi2B2C film ($T_c$ = 15.2K) in the superconducting (SC) state have been investigated. $R_d(V)$ contains clear "gap" features connected with processes of Andreev reflection at the boundary between normal metal and superconductor that allow the determination of the SC gap $\Delta$ and its temperature and magnetic field dependence. A distribution of $\Delta$ from ${\Delta }_{m}in\approx$ 1.5 meV to ${\Delta }_{m}ax\approx$ 2.4 meV is revealed; however the critical temperature $T_c$ in all cases corresponded to that of the film. The value 2${\Delta }_{m}ax/k_B{T}_c\approx$3.66 is close to the BCS value of 3.52, and the temperature dependence $\Delta (T)$ is BCS-like, irrespective of the actual $\Delta$ value. It is supposed that the distribution of $\Delta$ can be attributed to a gap anisotropy or to a multiband nature of the SC state in YNi2B2C, rather than to the presence of nodes in the gap.

6 two-column pages, 7 figs; V2: as published, Fig.4 is modified

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Cited by in corpus (10)

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• Point-contact spectroscopy of the antiferromagnetic superconductor HoNi2B2C in the normal and superconducting state
• On the interpretation of muon-spin-rotation experiments in the mixed state of type-II superconductors
• Superconducting order parameter in nonmagnetic borocarbides RNi${}_2$B${}_2$C (R=Y, Lu) probed by point-contact Andreev reflection spectroscopy
• Dominant $s$-wave superconducting gap in PdTe${}_2$ observed by tunneling spectroscopy on side-junctions
• Point-contact spectroscopy of the nickel borocarbide superconductor YNi2B2C in the normal and superconducting state
• Point-contact spectroscopy of the borocarbide superconductor YNi2B2C
• Point-contact study of the LuNi2B2C borocarbide superconducting film
• Andreev-reflection spectroscopy of SrPt3P single crystals