Evidence for multi-gap symmetry from grain boundary effects in polycrystalline Ba0.6K0.4Fe2As2 microbridge. (2nd November 2016)

• Record Type: Journal Article
• Authors: Huang, Ya; Zhou, Xian-Jing; Gao, Zhao-Shun; Wu, Hao; He, Ge; Yuan, Jie; Jin, Kui; Pereira, Paulo J; Ji, Min; An, De-Yue; Li, Jun; Hatano, Takeshi; Jin, Biao-Bing; Wang, Hua-Bing; Wu, Pei-Heng
• Is Part Of: Superconductor science & technology. Volume 30:Number 1(2017:Jan.)
• Publication Date: 2016-11-02
• Subjects: grain boundary effect -- Josephson junction -- multi-gap symmetry -- iron-based superconductors; 74.70.Xa -- 74.20.Rp -- 74.25.F- -- 74.78.Na; Superconductivity -- Periodicals; Superconductors -- Periodicals; 537.623
• DOI: 10.1088/0953-2048/30/1/015006
• Languages: English
• ISSNs: 0953-2048

Abstract

Abstract: We studied the grain boundaries within mechanically formed polycrystalline Ba 0.6 K 0.4 Fe2 As2 micro-bridges. By tunneling current across grain boundaries, current–voltage characteristics (IVCs) demonstrated the typical Josephson weak links behavior in micro-bridges. Shapiro steps were observed for the junctions under the microwave radiation at 10 GHz. The temperature dependence of the critical current I c was observed as a shoulder, corresponding to a multi-gap symmetry but not a single-gap s -wave or d -wave.