Anisotropic critical current density and flux pinning mechanism of Fe1+yTe0.6Se0.4 single crystals. (25th November 2021)

• Record Type: Journal Article
• Authors: Pan, Yongqiang; Zhou, Nan; Lin, Bencheng; Wang, Jinhua; Zhu, Zengwei; Zhou, Wei; Sun, Yue; Shi, Zhixiang
• Is Part Of: Superconductor science & technology. Volume 35:Number 1(2022)
• Publication Date: 2021-11-25
• Subjects: anisotropic critical current density -- flux pinning mechanism -- Fe1+yTe0.6Se0.4 -- magnetic relaxation; Superconductivity -- Periodicals; Superconductors -- Periodicals; 537.623
• DOI: 10.1088/1361-6668/ac3632
• Languages: English
• ISSNs: 0953-2048

Abstract

Abstract: Fe 1 + y Te0.6 Se0.4 has considerable application potential due to its large critical current density ( J c ) and high upper critical magnetic field ( H c2 ). However, the uncertainty of the anisotropy of J c and the unclear flux-pinning mechanism have limited the application of this material. In this study, the J c in three directions were obtained from magnetic hysteresis loop measurements. A large anisotropy of J c a b / J c c ∼ 10 was observed, and the origin of the anisotropy was discussed in details. Flux pinning force densities ( F p ) were obtained from J c, and a non-scaling behavior was found in the normalized pinning force f p [ F p / F p-max ] versus the normalized field h [ H / H c2 ]. The peaks of pinning force shift from a high h to a low h with increasing temperature. Based on the vortex dynamics analysis, the peak shift was found to originate from the magnetization relaxation. The J c and F p at critical states free from the magnetic relaxation were regained. According to the Dew-Hughes model, the dominant pinning type in Fe 1 + y Te0.6 Se0.4 clean single crystals was confirmed to be normal point pinning.