A route for a strong increase of critical current in nanostrained iron-based superconductors.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 27708268.
- Also identified by DOI 10.1038/ncomms13036 and PMC identifier 5059717.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The critical temperature T<sub>c</sub> and the critical current density J<sub>c</sub> determine the limits to large-scale superconductor applications. Superconductivity emerges at T<sub>c</sub>. The practical current-carrying capability, measured by J<sub>c</sub>, is the ability of defects in superconductors to pin the magnetic vortices, and that may reduce T<sub>c</sub>. Simultaneous increase of T<sub>c</sub> and J<sub>c</sub> in superconductors is desirable but very difficult to realize. Here we demonstrate a route to raise both T<sub>c</sub> and J<sub>c</sub> together in iron-based superconductors. By using low-energy proton irradiation, we create cascade defects in FeSe<sub>0.5</sub>Te<sub>0.5</sub> films. T<sub>c</sub> is enhanced due to the nanoscale compressive strain and proximity effect, whereas J<sub>c</sub> is doubled under zero field at 4.2 K through strong vortex pinning by the cascade defects and surrounding nanoscale strain. At 12 K and above 15 T, one order of magnitude of J<sub>c</sub> enhancement is achieved in both parallel and perpendicular magnetic fields to the film surface.