(Multi-)ferroic domain walls - a combined ab-initio and microscopical investigation

Interest in magnetoelectric multiferroic materials has increased exponentially over the last ten years, with considerable effort devoted both to combining magnetism and ferroelectricity in a single phase material and in obtaining magnetoelectric coupling between the two phenomena. Progress has been made on both front and a rich array of fundamental phenomena have been revealed in prototypical multiferroics such as bismuth ferrite, BiFeO3. Here we describe a new and previously unanticipated functionality: the observation – using conductive atomic force microscopy – of room temperature electronic conductivity at ferroelectric domain walls in BiFeO3. We explore the origin of the observed conductivity using high resolution transmission electron microscopy and first-principles density functional computations. Our results suggest the possibility of exploiting domain walls as a functional component in novel applications.