Transport Properties of Iron-Based $hbox{FeTe}_{0.5}hbox{Se}_{0.5}$ Superconducting Wire

摘要

${rm FeTe}_{0.5}{rm Se}_{0.5}$ superconducting wires have been fabricated using ex-situ PIT method with an Fe sheath. Among the other FeAs-based superconductors, ${rm FeTe}_{0.5}{rm Se}_{0.5}$ has great advantage for applications due to its binary composition and less toxicity. Surprisingly, superconducting current was observed in the as-fabricated wire without any heat treatments. The zero- resistivity critical temperature $(T_{rm c}^{rm zero})$ and transport critical current density $(J_{rm c})$ at 2 K were 3.2 K and 2.8 ${rm A}/{rm cm}^{2}$, respectively. In addition, by annealing at 200 $^{circ}{rm C}$ for 2 h, $T_{rm c}^{rm zero}$ and $J_{rm c}$ were enhanced up to 9.1 K, and 64.1 ${rm A}/{rm cm}^{2}$ , respectively. This suggests that the inter-grain connectivity was improved by heat treatment, and superconducting properties of ${rm FeTe}_{0.5}{rm Se}_{0.5}$ wire were enhanced.