Papers

May, 2011

As-NQR study of superconductivity in LaRAsO1-xFx (R=Fe and Ni)

JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
  • T. Oka
  • ,
  • T. Tabuchi
  • ,
  • Z. Li
  • ,
  • S. Kawasaki
  • ,
  • G. F. Chen
  • ,
  • J. L. Luo
  • ,
  • N. L. Wang
  • ,
  • Guo-qing Zheng

Volume
72
Number
5
First page
497
Last page
500
Language
English
Publishing type
Research paper (scientific journal)
DOI
10.1016/j.jpcs.2010.10.022
Publisher
PERGAMON-ELSEVIER SCIENCE LTD

We report As-75 nuclear quadrupole resonance (NQR) studies on oxypnictide superconductors LaFeAsO1-xFx (x=0.08, 0.15) and LaNiAsO1-xFx (x=0, 0.06, 0.10, 0.12). In LaFeAsO0.92F0.08 (T-c=23 K), nuclear spin-lattice relaxation rate 1/T-1 shows no coherence peak just below T-c and decreases with decreasing temperature accompanied by a hump structure at T similar to 0.4T(c), which is a characteristic of the multigap superconductivity. In the normal state, the quantity 1/T1T increases with decreasing temperature to T-c, indicating that the existence of antiferromagnetic correlation originating from its multiple electronic band structure. On the other hand, LaNiAsO1-xFx shows a clear Hebel-Slichter (coherence) peak just below T-c, evidencing that the LaNiAsO1-xFx is a BCS superconductor. In the normal state, 1/T-1 T is constant in the temperature range 4 <= T <= 10 K for all LaNiAsO1-xFx, which indicates electron correlations are weak. We suggest that the contrasting behavior of both superconductivity and electron correlations in LaFeAsO0.92F0.08 and LaNiAsO1-xFx between them relate to the difference of electronic band structure configuration. We also provide a possible interpretation for the pseudogap-like behavior in the normal state observed in both compounds. (C) 2010 Elsevier Ltd. All rights reserved.

Link information
DOI
https://doi.org/10.1016/j.jpcs.2010.10.022
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000291518100048&DestApp=WOS_CPL
ID information
  • DOI : 10.1016/j.jpcs.2010.10.022
  • ISSN : 0022-3697
  • Web of Science ID : WOS:000291518100048

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