Multiple superconducting gap and anisotropic spin fluctuations in iron arsenides: Comparison with nickel analog

Z. Li, S. Kawasaki, T. Oka, T. Tabuchi, Y. Ooe, M. Ichioka, Z. A. Ren, Z. X. Zhao, J. L. Luo, N. L. Wang, X. C. Wang, Q. Q. Liu, C. Q. Jin, C. T. Lin, Guo Qing Zheng

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

We present extensive 75As NMR and NQR data on the superconducting arsenides PrFeAs0.89F0.11 (T c=45K), LaFeAsO0.92F0.08 (Tc=27K), LiFeAs (Tc=17K) and Ba0.72K0.28Fe 2As2 (Tc=31.5K) single crystal, and compare with the nickel analog LaNiAsO0.9F0.1 (T c=4.0K). In contrast to LaNiAsO0.9F0.1 where the superconducting gap is shown to be isotropic, the spin lattice relaxation rate 1/T1 in the Fe-arsenides decreases below Tc with no coherence peak and shows a step-wise variation at low temperatures. The Knight shift decreases below Tc and shows a step-wise T variation as well. These results indicate spin-singlet superconductivity with multiple gaps in the Fe-arsenides. The Fe antiferromagnetic spin fluctuations are anisotropic and weaker compared to underdoped copper-oxides or cobalt-oxide superconductors, while there is no significant electron correlations in LaNiAsO 0.9F0.1. We will discuss the implications of these results and highlight the importance of the Fermi surface topology.

Original languageEnglish
Pages (from-to)492-496
Number of pages5
JournalJournal of Physics and Chemistry of Solids
Volume72
Issue number5
DOIs
Publication statusPublished - May 2011

Keywords

  • D. NMR
  • D. Superconductivity

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

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    Li, Z., Kawasaki, S., Oka, T., Tabuchi, T., Ooe, Y., Ichioka, M., Ren, Z. A., Zhao, Z. X., Luo, J. L., Wang, N. L., Wang, X. C., Liu, Q. Q., Jin, C. Q., Lin, C. T., & Zheng, G. Q. (2011). Multiple superconducting gap and anisotropic spin fluctuations in iron arsenides: Comparison with nickel analog. Journal of Physics and Chemistry of Solids, 72(5), 492-496. https://doi.org/10.1016/j.jpcs.2010.10.038