Naturally Layered Aurivillius Phases: Flexible Scaffolds for the Design of Multiferroic Materials

The Aurivillius layer-structures, described by the general formula Bi2O2(Am-1BmO3m+1), are naturally 2-dimensionally nanostructured. They are very flexible frameworks for a wide variety of applications, given that different types of cations can beaccommodated both at the A- and B-sites. In this review article, we describe how the Aurivillius phases are a particularly attractive class of oxides for the design of prospective single phase multiferroic systems for multi-state data storage applications, as they offer the potential to include substantial amounts of magnetic cations within a strongly ferroelectric system. The ability to vary m yields differing numbers of symmetrically distinct B-site locations over which the magnetic cations can be distributed and generates driving forces for cation partitioning and magnetic ordering. We discuss how out-of-phase boundary and stacking fault defects can further influence local stoichiometry and the extent of cation partitioning in these intriguing material systems.