Superconducting state of iron arsenide : 57Fe and 75As NMR studies

✍ Scribed by H. Nishimura; M. Yashima; H. Mukuda; Y. Kitaoka; K. Miyazawa; P.M. Shirage; K. Kiho; H. Kito; H. Eisaki; A. Iyo

• Book ID: 104084411
• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 229 KB
• Volume: 470
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/j.physc.2009.12.034

✦ Synopsis

We report 57 Fe and 75 As NMR measurements of the novel normal and superconducting-state characteristics of the iron-arsenide superconductor Ba 0:6 K 0:4 Fe 2 As 2 T c ¼ 38 K. In the normal state, the measured Knight shift and nuclear spin-lattice relaxation rate ð1=T 1 Þ demonstrate the development of wave-number (q)-dependent spin fluctuations, except at q ¼ 0, which may originate from the nesting across the disconnected Fermi surfaces. In the superconducting state, the spin component in the 57 Fe-Knight shift decreases down to zero with decreasing T, evidencing that a spin-singlet superconducting state is realized in Ba 0:6 K 0:4 Fe 2 As 2 .