Aurivillius phases: Non–superconducting materials?

Are aurivillius phases a new class of metal oxide superconductor? Recent reports in theliterature suggest that they are but this new study of these two-layered structures, such as Bi2WO6 (see figure) which contains fluorite-like Bi2O2 layers sandwiched by WO4 perovskite slabs, indicates that this is perhaps not the case. Electron microscopy and electron diffraction are used to probe these and related phases.