Iron-chalcogenide FeSe_0.5Te_0.5 coated superconducting tapes for high field applications

The high upper critical field characteristic of the recently discovered iron-based superconducting chalcogenides opens the possibility of developing a new type of non-oxide high-field superconducting wires. In this work, we utilize a buffered metal template on which we grow a textured FeSe_0.5Te _0.5 layer, an approach developed originally for high temperature superconducting coated conductors. These tapes carry high critical current densities (>1 × 10⁴ A/cm²) at about 4.2 K under magnetic field as high as 25 T, which are nearly isotropic to the field direction. This demonstrates a very promising future for iron chalcogenides for high field applications at liquid helium temperatures. Flux pinning force analysis indicates a point defect pinning mechanism, creating prospects for a straightforward approach to conductor optimization.