Chalcogen (O2, S, Se, Te) atmosphere annealing induced bulk superconductivity in Fe1+yTe1−xSex single crystal.

We reported a detailed study of Fe 1+ y Te 0.6 Se 0.4 single crystals annealed in the atmosphere of chalcogens (O 2 , S, Se, Te). After annealing with appropriate amount of chalcogens, Fe 1+ y Te 0.6 Se 0.4 single crystals show T c higher than 14 K with a sharp transition width ∼1 K. Critical current density J c for the annealed crystals reach a very high value ∼2–4 × 10 5 A/cm 2 under zero field, and is also robust under applied field at low temperatures. Magneto-optical imaging reveal that the J c is homogeneously distributed in the annealed crystals and isotropic in the ab -plane. Our results show that annealing in the atmosphere of chalcogens can successfully induce bulk superconductivity in Fe 1+ y Te 0.6 Se 0.4 . [ABSTRACT FROM AUTHOR]