Reversible critical current performance of FeSe0.5Te0.5 coated conductor tapes under uniaxial tensile strain

Abstract

FeSe0.5Te0.5 coated conductor as a kind of 11-type iron-based superconductor is currently attracting much attention. Recently, the bare FeSe0.5Te0.5 coated conductor tapes were developed by Shanghai Jiao Tong University and verified their superconductivity. For the future application, the FeSe0.5Te0.5 tapes should be subjected to the high electromagnetic forces and stress–strain. In this study, the authors encapsulated the bare FeSe0.5Te0.5 coated conductor tapes with copper layers to enhance the mechanical performance. The reversible critical current performance of the bare and the copper encapsulated FeSe0.5Te0.5 tapes under uniaxial tensile strain was tested. The critical currents of two kinds of tapes were measured over a wide range of applied uniaxial tensile strain by the U-shaped bending spring, respectively. The results show the critical performance of the bare FeSe0.5Te0.5 tapes decreases linearly with respect to tensile strain. The copper encapsulated FeSe0.5Te0.5 tapes have better performance than the bare tapes, with an irreversible tensile strain limit of 0.15%. In addition, the actual irreversible tensile strain limit of the copper encapsulated FeSe0.5Te0.5 tapes reaches 0.29% after considering the influence of the cooling process.