Doping Effect on Superconducting Transition of Ba-K-Bi-O System

Chemical doping or substitutions were carried out in both the Ba site and Bi site in Ba-K-Bi-O superconductor.The large single crystals of Ba-K-M-Bi-O(M=Ca,Eu,In and T1)were prepared by using the electrocrystallization method.The resulting crystalline materials were characterized by x-ray photoelectron spectroscopy and magnetic method.The results show that partial substitutions of Ca or Eu in the Ba site suppress T_(c) more drastically than that of TI in the Bi site.All the present chemical substitutions result in a decrease in T_(c).