Effect of Postannealing Process on Bi2Sr2.1Ca0.9Cu2O8+δ Textured Superconductors

Abstract

Bi-2212 samples prepared by the classical solid-state method have been grown from the melt using the Laser Floating Zone (LFZ) method. They have shown good grain alignment and transport critical current densities (J c ). After postannealing processes designed to produce the Bi-2212 phase controlled decomposition, J c values have been increased in an important manner. Maximum values have been achieved when samples were thermally treated at 680 °C for 168 h with improvements around 80 %, compared with the original textured samples. The results clearly indicate that postannealing processes, when adequately controlled, produce the formation of effective pinning centers which are responsible for the increase in the measured J c values.