34K superconductivity of Bi2201 system

In this paper it is analyzed that Bi2201 phase possesses strong incommensur ate modulation structure while T12201 phase does not show any modulation ch aracteristic, which is the origin of great difference between superconducti ng transition temperature of T12201 (T-c=90K) and Bi2201 (T-c=10K). Pb dopi ng was performed to weaken the modulation structure of Bi2201 system, and t hen by adjusting the oxygen concentration to optimal level, the Tc of Bi220 1 phase was improved to T-c(0) =34K (T-c(onset) =41K).