Ferroelectric Domains in Barium Titanate Nanostructures
A. Schilling, T.B. Adams, R.M. Bowman, J.M. Gregg, F.D. Morisson and J.F. Scott
Queen’s University and Nanotec Northern Ireland, UK
nanocapacitors, barium titanate, domains
Developing an understanding of the behaviour of ferroelectrics, which have been size-constrained into the nanoscale regime, has become a topic of intense research. However, experimentally, the fundamental influence of reduced dimensionality is frequently difficult to disentangle from various extrinsic influences that can alter both the state and dynamic properties of ferroelectrics. Ideally, the behaviour of free-standing nanoscale single crystal ferroelectric materials, that have already been heavily characterized in bulk, should act as a model system.
In this paper we will present progress in the understanding of the effects of reduced size on domain structures in free-standing single crystal BaTiO3, where size constraint has been introduced through the use of FIB milling; 1D and 3D nanostructures have been prepared and their properties investigated. STEM was used for imaging domain configurations within these size-constrained ferroelectrics. Decreasing the thickness increased the domain wall density, and interesting domain bifurcations on reduction of lamellar thickness were frequently seen. In toroids, domain behaviour was such that ‘herringbone’ domain patterns were frequently observed - presumably an energy minimizing configuration. Horizontal ladder-like domains are also present indicating a possible relaxed state and reproducing the orientation of the lamella domain walls. Combining FIB and STEM techniques proves to be a way forward in mapping and understanding domain configurations in novel 3D geometries.
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Nanotech 2006 Conference Program Abstract