CAREER: Structure Property Relationships in BiFeO3: A Defect Chemistry Approach

非技术描述：将开发一种新的方法，允许控制具有挥发性成分的薄膜复合氧化物的成分。这种技术将在铁酸铋中得到证明，铁酸铋是一种结晶固体，具有当前技术感兴趣的材料特性。这种新的处理方法将允许在纳米级上显著减少与组合物相关的缺陷，并且在这样做的过程中，提供电气性能的显著改善。最令人感兴趣的是铁酸铋耦合电场和磁场的能力：这种能力被广泛认为是新一代多功能传感，驱动和数据存储设备的基石。例如，提供前所未有的同时感测电场、声场和磁场的设备将被启用，并且对于远程监控等应用极具吸引力。只有实现这项研究提供的改进，才能充分利用这些机会。通过该计划的持续时间，至少有一名研究生和两名本科生将积极参与，每个夏季学期，该计划将支持材料科学教育推广活动。这项活动将包括为K-12科学教师举办的学习研讨会，重点是使K-12教育工作者能够将材料科学原理，特别是纳米级材料科学原理纳入他们的课程。技术知识：拟议的计划将探索缺陷化学，晶体结构和铁电薄膜的电学性质之间的基本关系。这项调查的基石涉及一种新的薄膜处理方法控制阳离子化学计量和点缺陷BiFeO 3通过气相平衡。这代表了对薄膜加工科学的基本贡献，因为几乎所有的商业和军用电子材料都依赖于部分通过缺陷平衡工程进行的性能优化。一个类似的复杂的能力还没有开发的电瓷薄膜，因此在薄膜性能工程的一个重大机会仍然没有开发。所提出的合成技术将使这种优化在许多系统举行的承诺，戏剧性的性能改善，并洞察到缺陷相关的现象。在他们的研究过程中，参与的研究生和本科生将开发一种先进的气相/凝相平衡方法，用于积极调整缺陷平衡。在这样做的过程中，他们将确定薄膜中的缺陷平衡-性能关系，这代表了材料科学的重要进步，特别是在纳米级，缺陷的影响变得更加明显。

NON-TECHNICAL DESCRIPTION: A new methodology allowing composition control of thin film complex oxides with a volatile constituent will be developed. This technique will be demonstrated in bismuth ferrite, which is a crystalline solid having material properties of current technological interest. This new processing approach will allow dramatic reduction composition-related defects at the nanoscale, and in doing so, provide for dramatic improvements in the electrical properties. Of premier interest is the ability of bismuth ferrite to couple electrical and magnetic fields: this capability is widely regarded as the cornerstone of a new generation of multifunctional sensing, actuating, and data storage devices. For example, devices offering unprecedented and simultaneous sensing of electrical, acoustic, and magnetic fields will be enabled, and are extremely attractive for applications such as remote surveillance. These opportunities can be fully harnessed only if the improvements offered by this research are realized. Through the duration of this program, a minimum of one graduate student and two undergraduate students will be active participants, and each summer semester, this program will support a Materials Science educational outreach activity. This activity will involve learning workshops for K-12 science teachers, which focus on empowering K-12 educators to incorporate the Principles of Materials Science, specifically at the nanoscale, to their curriculum.TECHNICAL DETAILS: The proposed program explores fundamental relationships between defect chemistry, crystalline structure, and the electrical properties of ferroelectric thin films. The cornerstone of this investigation involves a novel thin film processing methodology controlling cation stoichiometry and point defects in BiFeO3 through gas-phase equilibrium. This represents a fundamental contribution to thin film processing science since nearly all commercial and military electronic materials rely on property optimization in part through defect equilibrium engineering. A similarly sophisticated capacity has not been developed for electroceramic thin films, thus a major opportunity in thin film property engineering remains untapped. The proposed synthesis technique will enable this optimization in numerous systems holding promise for dramatic property improvement, and insight into defect-related phenomena. In the course of their research, the participating graduate and undergraduate students will develop a cutting-edge gas-phase/condensed-phase equilibrium method for actively tuning defect equilibria. In doing so, they will identify defect equilibria - property relationships in thin films, which represents an important advancement in Materials Science, especially at the nanoscale, where the impact of defects becomes more pronounced.