Hydrothermal synthesis of a new Bi-based (Ba0.82K0.18)(Bi0.53Pb0.47)O3 superconductor

Abstract A new type of bismuth-oxide-based superconductor was prepared by a hydrothermal reaction at 240 °C. The synchrotron X-ray powder diffraction pattern reveals a simple perovskite-type structure with a cubic cell of a  = 4.28877(1) A with space group Pm - 3 ¯ m . The chemical composition of this cubic perovskite oxide was formulated as (Ba 0.82 K 0.18 )(Bi 0.53 Pb 0.47 )O 3 after structural refinement using synchrotron X-ray powder diffraction and chemical analysis data. The cubic microstructure and compositional homogeneity were confirmed by scanning electron microscopy analysis. This compound exhibited a diamagnetic signal with a shielding volume fraction of ∼64% with an onset of approximately 22.8 K. Its resistivity started to drop at ∼15 K, and zero resistivity was observed below 4 K. The thermal decomposition of this simple perovskite structure started above 600 °C. Finally, the calculated band structure also exhibited metallic behavior at ambient conditions.