Karin M. Rabe
Rutgers University
Friday, April 28, 2006
4:00 pm in SPL 57
Designer Oxides that Work
Abstract: Ferroelectric materials have characteristic properties valuable for technological applications, due to their uniform electrical polarization switchable by an applied electric field. The large family of perovskite oxide ferroelectrics has additional useful properties, most notably strong coupling between polarization and strain resulting in large piezoelectric coefficients. Using atomic-scale layering and epitaxial strain, we can imagine reassembling known perovskite compounds to produce artificially structured ferroelectric oxides with desirable properties. With continuing progress both in experimental and first-principles theoretical techniques, this challenging approach to the design of new ferroelectric materials is finally becoming a reality. As an example, I will describe the design and experimental realization of high-polarization ferroelectrics based on layered structures combining the perovskite oxides BaTiO3, PbTiO3, CaTiO3, and SrTiO3. From first-principles calculations predicting the atomic arrangements and polarization of these structures, we have developed a simple conceptual model that guides the design process. By incorporating perovskite oxides and related structural families with other properties, this superlattice approach could eventually be extended to a large parameter space of artificially structured oxides with desirable ferroelectric properties and with novel combinations of ferroelectricity with other properties, including magnetism.
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