Floating zone Ag doped (Bi 1·6 Pb 0·4 )Sr 2 CaCu 2 O 8+ δ textured rods

Abstract

In this work, superconducting samples of (Bi_1.6Pb_0.4)Sr₂CaCu₂O_8+δ+3 wt.%Ag have been studied and compared with Ag free samples, (Bi_1.6Pb_0.4)Sr₂CaCu₂O_8+δ, and with Ag and Pb free ones, Bi₂Sr₂CaCu₂O_8+δ. It has been found that Pb doped samples present a worse texture when compared with the undoped ones, resulting in a drastic change on the microstructure. The results showed that electrical resistivity at room temperature, critical current as well as flexural strength are decreasing for the Pb doped samples. When Ag is added to these Pb doped samples, all the properties are improved even if they do not reach the same values as the undoped ones. On the other hand, it has been found that Pb doped samples showed E–I curves with very high sharpness values on the zone of the superconducting to normal transition, reaching n values (E∼Iⁿ) as high as 45 at 65 K, for samples with simultaneous Pb and Ag additions.