Anisotropic spin fluctuations and multiple superconducting gaps in hole-doped Ba0.72K0.28Fe2As2: NMR in a single crystal

K. Matano, Z. Li, G. L. Sun, D. L. Sun, C. T. Lin, M. Ichioka, Guo Qing Zheng

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64 Citations (Scopus)


We report the75As-NMR study on a single crystal of the hole-doped iron-pnictide superconductor Ba0.72K0.28Fe 2As2(Tc = 31.5 K). We find that the Fe antiferromagnetic spin fluctuations are anisotropic and are weaker compared to underdoped copper-oxides or cobalt-oxide superconductors. The spin lattice relaxation rate 1/T1 decreases below Tc with no coherence peak and shows a stepwise variation at low temperatures, which is indicative of multiple superconducting gaps, as in the electron-doped Pr(La)FeAsO 1-xFx. Furthermore, no evidence was obtained for a microscopic coexistence of a long-range magnetic order and superconductivity.

Original languageEnglish
Article number27012
JournalEurophysics Letters
Issue number2
Publication statusPublished - Jul 1 2009

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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