Anomalous anisotropy of critical currents in (Sr, K)Fe2As2 tapes. (6th February 2017)

• Record Type: Journal Article
• Authors: Awaji, Satoshi; Nakazawa, Yushiro; Oguro, Hidetoshi; Tsuchiya, Yuji; Watanabe, Kazuo; Shimada, Yusuke; Lin, He; Yao, Chao; Zhang, Xianping; Ma, Yanwei
• Is Part Of: Superconductor science & technology. Volume 30:Number 3(2017:Mar.)
• Publication Date: 2017-02-06
• Subjects: Fe-based superconductor -- critical current -- anisotropy -- powder in tube wire; Superconductivity -- Periodicals; Superconductors -- Periodicals; 537.623
• DOI: 10.1088/1361-6668/aa56fd
• Languages: English
• ISSNs: 0953-2048

Abstract

Abstract: We measured critical currents and irreversibility fields of Ag-sheath (Sr, K)Fe2 As2 tapes at various temperatures, magnetic fields and magnetic field directions. The sample tapes were made by a powder-in-tube with a hot-press process in the final heat treatments. The inverse anisotropy in J c in comparison with the effective mass anisotropy can be found in the hot-pressed (Sr, K)Fe2 As2 tapes. We found that the broad c -axis peak in angular dependence of J c appears in a low field region and it decreases with increasing field and temperature. In addition, the crossover of J c anisotropy appears around 10 T at 4.2 K and the crossover field decreases with increasing temperature. It is considered that these unusual anisotropic J c behaviors may be originated by the strong random pinning center which is larger than the coherence length,