Vortex Structure and Anisotropic Superconducting Gaps in Ba[Fe(Ni)]${}_2$As${}_2$

Abstract

We studied nearly optimally Ni-substituted BaFe${}_{2-x}$Ni${}_x$As${}_2$ (BFNA) single crystals with $T_C\approx 18.5$\,K. In irreversible magnetization measurements, we determined the field dependence of the critical-current density and discuss the nature of observed strong bulk pinning. Using intrinsic multiple Andreev reflections effect (IMARE) spectroscopy, we directly determine two distinct superconducting gaps and resolve their moderate anisotropy in the momentum space. The BCS-ratio for the large gap $2{\Delta }_L/k_B{T}_C>4.1$ evidences for a strong coupling in the ${\Delta }_L$-bands.

6 pages, 4 figures. To be published in Proceedings of Superstripes 2016 Conference

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Cited by in corpus (4)

• On the Structure of Superconducting Order Parameter in High-Temperature Fe-Based Superconductors
• Optical and Hidden Transport Properties of BaFe${}_{1.91}$Ni${}_{0.09}$As${}_2$ Film
• THz electrodynamics of BaFe${}_{1.91}$Ni${}_{0.09}$As${}_2$ film analyzed in the framework of multiband Eliashberg theory
• Lattice, Charge and Spin phase inhomogeneity in complex striped quantum matter