Annealing evolution of the flux pinning in well-textured Bi-2212 thin rods

Abstract

The evolution of the flux pinning energy distribution, irreversibility line shift, critical current and voltage–current characteristics of well-textured Bi-2212 thin rods with annealing is reported. The results confirm an important enhancement of the intergranular pinning with the annealing time, while the intragranular components do not change significantly. Improvement of most superconducting parameters with the annealing time has been found. A self-field limited current model, which includes the flux pinning by planar high- J c (small angle) grain boundaries, has been used to fit the electric transport at high temperatures. The comparisons of the results with the model point out that the energy losses appear before reaching full current penetration of the rods. Moreover, the local J c is almost constant with annealing time and only an external part of the rod cross-section, which increases with annealing time, is used for the current transport.