2008/03/31 by Zheng Li, Z. Li, Gengfu Chen +17 · 4 citations
Materials Science · Physics and Astronomy · #Iron-based superconductors research #Rare-earth and actinide compounds #Superconductivity in MgB2 and Alloys #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.78.060504
published as Phys. Rev. B, 78, 060504(R), 2008 · 4 pages, 4 figures
arxiv created 2008/04/07 · openalex publication_date 2008/08/18 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
A series of layered nickel-based LaNiAsO_1\ensuremath-xFx compounds with x=0--0.15 are synthesized by solid-state reactions. The pure LaNiAsO exhibits bulk superconductivity with Tc\ensuremath∼2.75 K. Partial substitution of oxygen with fluorine increases the transition temperature to \ensuremath∼3.8 K. The LaNiAsO0.9F0.1 sample shows a sharp superconducting transition and a sharp specific-heat jump at the critical temperature. The magnitude of the specific-heat jump is much larger than that expected from the weak-coupling BCS theory, indicating that this superconductor is in the strong-coupling regime. Furthermore, the temperature dependence of the specific heat deviates strongly from the theoretical result for the single-band s- or d-wave superconductor but shows a characteristic feature of multigap.