Ceramics in the perovskite family have useful properties and are encountered in applications including electroceramics, superconductors, refractories, catalysts, magnetoresistors, spintronics, and proton conductors. Understanding the way crystal defects, which are very common in all engineering ceramics, affect structure and thereby properties is of great importance to both science and industry. Models which aid the prediction of structure and, by extension, properties are extremely useful in both the understanding and designing of materials with engineered properties without expensive trial and error, yet existing theoretical models are inadequate to describe such ceramics. Their dual approach to this problem involves both an experimental component, using a well-chosen representative perovskite system, plus a theoretical computational component. This combined approach may result in much higher quality functional ceramics, and the impact on the $350-billion cellular telecommunications industry alone could include more efficient filters leading eventually to higher data rates for multimedia applications and ultimately a reduction in the overall number of cellular masts required. Outreach to the greater community will occur via the Jason Project, Family Engineering Day, the annual "BSU Day with the Legislators", the UIUC Minority Outreach and Retention Program, UIUC Engineering Open House, and "Project Lead the Way" for secondary teachers. In addition, a web site created and maintained by project participants will become a useful tool for teaching aspects of solid-state chemistry as well as materials science and technology; therefore, funding continues to support their multi-faceted and highly successful outreach activities.
TECHNICAL DETAILS: Models which aid the prediction of structure and, by extension, properties are extremely useful in both the understanding and designing of materials with engineered properties without expensive trial and error, yet existing theoretical models are inadequate to describe such ceramics. Their experimental approach using a well-chosen representative perovskite system, on the other hand, overcomes these shortcomings and has already been successfully demonstrated. In this project, several complex ceramic compositions are being synthesized via an advanced chemical processing method, the resulting crystal structures analyzed, and properties measured in order to complete a predictive structural model. Computational structural models are simultaneously being developed to verify and complement the empirically derived ones, adding an additional dimension of understanding to the modeling of structure and phase transitions. The predictive models could then be used to find new perovskites with new and interesting properties. The educational impact of the project is strong and varied. The international exposure gained by the students involved, who will be trained in cutting-edge characterization techniques including neutron diffraction and transmission electron microscopy, will be formative and extremely valuable for their future careers.
