Bi2−xPbx(Ca, Sr)n+1CunO2n+4+δ (n = 1, 2, 3, and 4) family of superconductors

Superconducting oxides of the Bi1.5Pb0.5(Ca, Sr) n+1Cu n O2n+4+δ series with n = 1, 2, 3 and 4 have been characterized. The superconducting transition temperature increases markedly with n up to n = 3, but the T c of the n = 4 member is not much higher than that of the n = 3 member. The T c does not change significantly in Bi2−x Pb x CaSr2Cu2O8+δ with x (0.1 < x ≤ 0.5).