Effects of Pb Content on the Formation of the High-Tc Phase in the (Bi, Pb)-Sr-Ca-Cu-O System

Formation of the high-T c phase in the (Bi, Pb)-Sr-Ca-Cu-O system was studied using specimens with various Bi/Pb ratios. The synthesis temperature was suppressed as the Pb/(Pb+Bi) was increased. The lattice constant of the c axis of the low-T c phase (T c∼80 K) and high-T c phase (T c∼105 K) increased with increasing Pb content. Substitution of 30% Pb for Bi was found to be most preferential for the formation of the high-T c phase.