In the history of superconductors, Fe-based superconductor LnFePnO1-xFx (1111) has the highest Tc at ~58K except Cu-based oxide superconductors. Electron doping by substitution of O2- with F- was essential to induce superconductivity. Local structures around iron are found to have a good empirical relation to Tc. Maximum Tc is observed for 1111 materials having nearly regular tetrahedral FeAs4 local structures. The Tc and upper critical field of 1111 compounds are very attractive for power cable under high magnetic fields, although fabrication of practical superconducting wires is a tough challenge due to the difficulty in controlling the F contents during a processing for ex-situ powder-in-tube method.
|Photonic and Electronic Properties of Fluoride Materials: Progress in Fluorine Science Series
|Published - 2016 3月 15
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