Investigation of the two-phase transition of Pb-free Bi2Sr2Ca(n−1)CunO(2n+4)+δ (n=3) via the peak behavior in the out-of-phase AC magnetic susceptibility
Abstract
AC magnetic susceptibility was measured on Pb-free Bi-2223 at various frequencies and applied fields. The usual hump in the real part (χ') and double peak features in the imaginary part (χ") was observed. It was concluded that these features cannot be attributed to a single-phased transition because each peak reveals a shift when the field is varied with respect to temperature. This indicates that two superconducting phases are present, one belonging to the Bi-2223 phase and the other belonging to Bi-2212 phase. XRD also shows the coexistence of the present phases formed.