An electron diffraction and group theoretical study of the new Bi-based high-temperature superconductor
An electron microscopy study of the new Bi-based high-temperature superconductor reveals an incommensurately modulated, pseudo-tetragonal, layered structure strongly reminiscent of the so-called Aurivillius phases. The systematic extinction conditions associated with the matrix and satellite reflections allow two possible space group symmetries for the average structure and two possible superspace