The Role of Point Defects in the Structure and Properties of Perovskites for Functional Applications

非技术描述：钙钛矿系列陶瓷具有有用的性能，在电陶瓷、超导体、耐火材料、催化剂、磁敏电阻、自旋电子学和质子导体等应用中都会遇到。晶体缺陷在所有工程陶瓷中非常常见，了解晶体缺陷对结构和性能的影响对科学和工业都具有重要意义。有助于预测结构和性能的模型在理解和设计具有工程性能的材料时都非常有用，而不需要昂贵的试验和错误，但现有的理论模型不足以描述此类陶瓷。他们解决这个问题的双重方法既包括使用精心挑选的代表性钙钛矿系统的实验部分，也包括理论计算部分。这种结合的方法可能会产生更高质量的功能陶瓷，仅对价值3500亿美元的蜂窝电信行业的影响就可能包括更高效的过滤器，最终导致多媒体应用的更高数据速率，并最终减少所需的蜂窝天线塔的总数量。我们将透过Jason计划、家庭工程日、一年一度的“北卡罗来纳州立大学立法者日”、UIUC少数族裔外展及保留计划、UIUC工程学开放日，以及为中学教师而设的“领路计划”，向更广泛的社区推广。此外，由项目参与者创建和维护的网站将成为教授固态化学和材料科学与技术方面的有用工具；因此，资金继续支持他们多方面和非常成功的外展活动。技术细节：有助于预测结构和性能的模型在理解和设计具有工程性能的材料方面都非常有用，而不需要昂贵的试验和错误，然而现有的理论模型不足以描述这种陶瓷。另一方面，他们的实验方法使用了精心挑选的具有代表性的钙钛矿系统，克服了这些缺点，并已被成功证明。在这个项目中，通过一种先进的化学处理方法合成了几种复杂的陶瓷成分，分析了产生的晶体结构，并测量了性能，以完成预测结构模型。同时正在开发计算结构模型，以验证和补充经验派生的模型，为结构和相变的建模增加了一个额外的理解维度。然后，预测模型可以用来寻找具有新的有趣特性的新钙钛矿。该项目的教育影响是强烈和多样的。参与其中的学生将接受包括中子衍射和透射电子显微镜在内的尖端表征技术的培训，他们获得的国际接触将是形成的，对他们未来的职业生涯非常有价值。

NON-TECHNICAL DESCRIPTION: 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.