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 Tl) were prepared by using the electrocr ystallization method. The resulting crystalline materials were charact erized by x-ray photoelectron spectroscopy and magnetic method. The re sults show that partial substitutions of Ca or Eu in the Ba site suppr ess T(c) more drastically than that of Tl in the Bi site. All the pres ent chemical substitutions result in a decrease in T(c).