The electric field jump—detection of damaged Nb barrier in MgB2 wires annealed under pressure. (15th September 2015)

• Record Type: Journal Article
• Authors: Gajda, D; Zaleski, A J; Morawski, A; Rindfleisch, M; Thong, C; Tomsic, M
• Is Part Of: Superconductor science & technology. Volume 28:Number 11(2015:Nov.)
• Publication Date: 2015-09-15
• Subjects: damaged Nb barrier -- critical current -- MgB2 wires; 74.25.F -- 74.70.Ad.; Superconductivity -- Periodicals; Superconductors -- Periodicals; 537.623
• DOI: 10.1088/0953-2048/28/11/115003
• Languages: English
• ISSNs: 0953-2048

Abstract

Abstract: In this paper we present the results of critical current ( I c ) measurements of MgB2 wires made with two different set-ups of the four-point probe method: current sweep type—constant magnetic field and increasing current, and field sweep type—constant current and rapidly increasing magnetic field. Results from magnet field sweep type measurements can be interpreted by a new physical concept—a jump of the electric field in low magnetic fields. This physical concept can be correlated with damages in the Nb-barrier existing in the MgB2 wire and be employed as a detection scheme. The damage in Nb barrier reduces critical current density ( J c ) and complicates the study on critical temperature ( T c ), upper critical field ( B c2 ), irreversible magnetic field ( B irr ), pinning force ( F p ), and pinning centers in superconducting MgB2 wires. Our proposed method to detect damages in Nb barrier would benefit efforts in development and applications of MgB2 wires.