Irreversibility fields of Bi-2223 at 30-77 K

Abstract

Abstract-Significant differences exist, of order a factor of two, in irreversibility field at 77 K of Ag-clad (Bi,Pb) 2 Sr 2 Ca 2 Cu 3 O (Bi-2223) composites from different sources. In the present case, we have studied the 30-77 K irreversibility field and performance of post annealed Bi-2223 samples. Post annealing in the temperature range 800-750 C significantly raises both and the irreversibility field. At 77 K, the irreversibility field was characterized both by the decrement field, , defined by ( )