Type-II superconductivity in W5Si3-type Nb5Sn2Al. (1st March 2019)

• Record Type: Journal Article
• Authors: Wu, Jifeng; Liu, Bin; Cui, Yanwei; Wang, Hangdong; Wang, Zhicheng; Ren, Zhi; Cao, Guanghan
• Is Part Of: Superconductor science & technology. Volume 32:Number 4(2019:Apr.)
• Publication Date: 2019-03-01
• Subjects: superconductivity -- ternary aluminide -- W5Si3-type structure; Superconductivity -- Periodicals; Superconductors -- Periodicals; 537.623
• DOI: 10.1088/1361-6668/ab0453
• Languages: English
• ISSNs: 0953-2048

Abstract

Abstract: We report the discovery of superconductivity (SC) in the ternary aluminide Nb5 Sn2 Al, which crystallizes in the W5 Si3 -type structure with one-dimensional Nb chains along the c -axis. It is found that the compound has a multiband nature and becomes a weakly coupled, type-II superconductor below 2.0 K. The bulk nature of SC is confirmed by the specific heat jump, whose temperature dependence shows apparent deviation from a single isotropic gap behavior. The lower and upper critical fields are estimated to be 2.0 mT and 0.3 T, respectively. From these values, we derive the penetration depth, coherence length and Ginzburg–Landau parameter to be 516 nm, 32.8 nm and 15.6, respectively. In contrast, the isostructural compound Ti5 Sn2 Al does not superconduct above 0.5 K. A comparison of these results with other W5 Si3 -type superconductors suggests that T c of these compounds correlates with the average number of valence electrons per atom.