Materials World Network: Experimental Observation and Theoretical Modeling of Domain Evolution in Ferroelectrics

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This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Ferroelectric ceramics have unique properties, including piezoelectricity, pyroelectricity, the electro-optic effect, phase change, and polarization switching. These special properties make them useful for a wide range of technological applications. For example, medical ultrasound scanners, random access memories, infrared camera sensors, electro-optic modulators, sonar beacons, vibration controllers, and diesel engine fuel injectors all make use of ferroelectric materials. The proposed research program will advance the field of experimental and theoretical characterization of the behavior of ferroelectric materials. Experimental and theoretical methods developed in this program will be applicable to the study of other "smart" materials including shape memory alloys and ferromagnetic shape memory alloys. Through this research, doctoral students will be trained in a collaborative project with international activity: students will train at University of Texas, Austin, and University of Oxford (UK). To broaden participation from underrepresented groups the principal investigators will continue their track record of leveraging institutional resources to recruit women and minority students. The research will ultimately benefit society by developing a fundamental understanding of the behavior ferroelectric materials, which will support and stimulate the design of novel ferroelectric devices for numerous and diverse technological applications.The merit of this Materials World Network international collaborative research program originates from the joint application of state of the art experimental characterization (in the UK) and theoretical modeling (in the US) of domain structure nucleation, growth and evolution in single crystal ferroelectric ceramics. To date there have been several outstanding experimental and theoretical studies on ferroelectric crystals, but none of these studies has systematically integrated experimental observations that can critically test model predictions with a modeling framework that is, in turn, able to suggest innovative experimental studies. The experimental component of the research uses atomic and piezo-force microscopy, X-ray sychrotron, and birefringence methods to directly observe ferroelectric domain structure evolution under thermal, electrical and mechanical loadings. Each experimental configuration is also studied and interpreted through the lens of detailed numerical solutions of the Landau-Ginsburg-Devonshire phase-field equations. The studies focus on two categories: (1) evolution of existing structures including isolated domain walls subjected to static and alternating fields, and the evolution of domain needles and domain vortices, and (2) the nucleation of domain structures due to cooling through the Curie temperature, and from field concentrators like electrode tips and material inclusions. During the course of the research, two doctoral students will be trained in a strongly collaborative project with international activity. Each student will spend six months in the counterpart institution, with these exchanges timed to allow the research students to work together and thus gain expertise in both theoretical and experimental methods. The detailed experimental characterization and predictive modeling of domain structure evolution from this research will support and stimulate the design of the next generation of novel ferroelectric devices.