Transformation of Superconducting Phases in (Bi, Pb)-Sr-Ca-Cu-O during Post-Annealing

Abstract
(Bi, Pb)SrCaCuO superconducting films have been successfully obtained from single-target DC sputtering, deposited on (100) MgO substrate, followed by an appropriate annealing treatment. By varying the post-annealing temperature and time, we can have 9 K (2201) or 80 K (2212) superconducting phase as desired. It is particularly interesting to find that the two phases can be transformed from one to the other reversibly, as confirmed by both crystal structure and transport measurement.