Superconductive transition at 98.5 K in monoclinic (Bi,Pb)2Sr2CaCu2Oy

Abstract
By annealing the (Bi1x Pbx )2 Sr2 CaCu2 Oy superconductor (2:2:1:2 phase) with x=0.2 in the absence of oxygen, a high-Tc value of 98.5 K was observed. The lattice of this superconductor was revealed to be monoclinic. The formation of this superconductor with an unexpectedly high Tc value for the 2:2:1:2 phase is difficult to explain simply by consideration of the optimum carrier concentration, and it is likely correlated with the structural transformation of the superconductor.