Effect of annealing and quenching on superconductivity in Pb and Sb-doped Bi2Sr2Ca2Cu3O x

Abstract

Samples of the series Bil.9_xPbxSbo.tSr2Ca2Cu30 r with x = 0, 0"l, 0.2, 0-3 and 0.4 were prepared by the solid-state route. The X-ray and d.c. electrical resistivity data on furnace-cooled and quenched samples are presented. Though the starting composition is 2223, the end products were multiphase with 4334 as the major phase. A superconducting transition with T~ = 100 K was observed in the pure 2223 sample after quenching. The furnace-cooled samples were metallic, while samples with x=0.1, 0-2 and 0'3 were superconducting after quenching. The amount of the 4334 phase decreases with increasing Pb content. Quenching seems to be favourable for the formation of the 4334 phase.