Two (Bi,Pb)-oxycarbonate superconductors have been found by resistivity and magnetization measurements. Transition temperatures are 41 K (54K) for the low-Tc phase (high-Tc phase). The crystal structures were analyzed by using the HRTEM and X-ray diffraction techniques. The lattice parameters were a0=3.821 A ̊, c0=39.444 A ̊ (a0=3.88 A ̊, c0=54.52 A ̊) for low-Tc phase (high-Tc phase) in the tetragonal unit cell. A crystal structure model is proposed in which the chemical formula for the low-Tc phase (high-Tc phase) is (Bi,Pb)2Sr4Cu2 CO3O8 ((Bi,Pb)2Sr6Cu3(CO3)2O10), which can be described as the combination of a single (double) Sr2CO3 block and a single (Bi,Pb)2Sr2O4 block.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering