Effects of compositional variations on the properties of superconducting (Bi,Pb)2Sr2Ca2Cu3Oδ

Abstract
The results of a systematic study on compositional variations within the Bi2−xPbxSr2Ca2Cu3Oδ superconducting system are reported. It is found that a secondary phase (or phases), likely composed of Pb‐Sr‐Ca‐Cu‐O, forms when x exceeds 0.35, indicating that this is an upper limit on the amount of Pb which replaces Bi. Varying the Sr:Ca or Bi:Ca ratio has dramatic effects on the resistive and magnetic properties. It is suggested that there is a very limited range of solution among the alkaline‐earth elements. Bi occupying Ca sites is probably deleterious for both Tc and the structural stability of the 2223 phase. Preliminary results on textured ceramic samples have yielded Jc (77 K) as high as 580 A/cm2 .