Superconducting and normal-state properties of single-crystalline Tl0.47Rb0.34Fe1.63Se2 as seen via 77Se and 87Rb NMR

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Author(s)

  • Long Ma
  • G. F. Ji
  • J. Zhang
  • J. B. He
  • D. M. Wang
  • G. F. Chen
  • Weiqiang Yu

Detail(s)

Original languageEnglish
Article number174510
Journal / PublicationPhysical Review B - Condensed Matter and Materials Physics
Volume83
Issue number17
Publication statusPublished - 1 May 2011
Externally publishedYes

Abstract

We report both 77Se and 87Rb nuclear magnetic resonance (NMR) studies on Tl0.47Rb0.34Fe1.63Se2 single-crystalline superconductors (Tc ≈ 32 K). Singlet superconductivity is suggested by a sharp drop of the Knight shift K(T) below Tc , after subtracting the superconducting diamagnetic effect. However, the Hebel-Slichter coherence peak below T is not observed in the spin-lattice relaxation rate 1/T1 , even with a low in-plane NMR field of 2.6 T. Just above Tc , no evidence of low-energy spin fluctuation is found in the spin-lattice relaxation rate on both the 77Se and 87Rb sites. Upon warming, however, the Knight shifts and the spin-lattice relaxation rates of both nuclei increase substantially with temperature. In particular, the Knight shift is nearly isotropic and follow a function fit of= a+bT2 from Tc up to 300 K. Our observations should put a strong constraint to the theory of magnetism and superconductivity in the recently discovered iron selenide superconductors. 

Citation Format(s)

Superconducting and normal-state properties of single-crystalline Tl0.47Rb0.34Fe1.63Se2 as seen via 77Se and 87Rb NMR. / Ma, Long; Ji, G. F.; Zhang, J. et al.
In: Physical Review B - Condensed Matter and Materials Physics, Vol. 83, No. 17, 174510, 01.05.2011.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review