Basic Research in Antiferroelectric Perovskites

反铁电钙钛矿基础研究

• 批准号: 9988853
• 负责人: I-Wei Chen
• 金额: $ 43.69万
• 依托单位: University of Pennsylvania
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-07-01 至 2003-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9988853&HistoricalAwards=false
• 关键词: Basic; Research; Antiferroelectric; Perovskites

9988853ChenThe objective of this proposal is to investigate fundamental materials problems concerning antiferroelectric perovskites. Antiferroelectric perovskites are a small subclass of ferroic perovskites. Compared to prototypical ferroelectric perovskites, they have relatively limited applications to date and have been much less studied in the past. Nevertheless, theoretical considerations indicate that the antiferroelectric states are energetically similar to the ferroelectric states, and that in many large-response ferroelectrics there is a strong antiferroelectric/ferroelectric competition that is central to latter's outstanding properties. Moreover, several physical and chemical features common to nearly all of the antiferroelectric perovskites, e.g., a negative transformation volume and a very weak isotope effect, are anomalous and not found in any ferroelectric perovskites. This suggests that new basic research on antiferroelectric perovskites will have a fundamental impact on ferroelectrics that are used for important technological and biomedical applications. It also has the potential of discovering novel ferroelectrics and antiferroelectrics with attractive physical and chemical properties. In this research project, the PI will determine mechanical and electrical field effects on antiferroelectric-ferroelectric transitions, interrogate local atomic and electronic structures of antiferroelectric perovskites, and investigate antiferroelectric thin films and heterostructures. Using concepts in crystal chemistry and statistical physics, experiments will be designed to optimize antiferroelectric interactions and tune their competition with ferroelectric interactions. Synchrotron x-ray and other scattering and imaging techniques will be used to probe the cation couplings and electronic transitions that may give rise to the anomalous features observed in antiferroelectricity. This study will be further complemented by property characterization of bulk and thin film antiferroelectrics to understand the thermodynamics and kinetics of phase transitions, interface motion, interface-defect interactions, and antiferroelectric/ferroelectric competition at the smallest length scale. Antiferroelectric perovskites are a type of perovskites that have had relatively limited applications to date and have been much less studied in the past. Nevertheless, theoretical considerations indicate that these materials may have unique properties and thus basic research on them will have a fundamental impact on ferroelectrics that are used for important technological and biomedical applications. The project will train Ph.D. students as well as offering training to undergraduates and high school teachers. This effort will be integrated into the research project to attract traditional and non-traditional students and to provide them laboratory and research opportunities.

本文的目的是研究反铁电钙钛矿材料的基本材料问题。反铁电钙钛矿是铁性钙钛矿的一个子类。与典型的铁电钙钛矿相比，它们迄今为止的应用相对有限，并且过去的研究少得多。然而，理论上的考虑表明，反铁电态在能量上与铁电态相似，并且在许多大响应铁电体中，存在强烈的反铁电/铁电竞争，这是后者杰出特性的核心。此外，几乎所有的反铁电钙钛矿都具有几个共同的物理和化学特征，例如，负的转变体积和非常弱的同位素效应是反常的，并且在任何铁电钙钛矿中都没有发现。这表明，对反铁电钙钛矿的新基础研究将对用于重要技术和生物医学应用的铁电体产生根本性影响。它还具有发现具有吸引人的物理和化学性质的新型铁电体和反铁电体的潜力。在这个研究项目中，PI将确定机械和电场对反铁电-铁电转变的影响，询问反铁电钙钛矿的局部原子和电子结构，并研究反铁电薄膜和异质结构。使用晶体化学和统计物理学的概念，实验将被设计为优化反铁电相互作用，并调整它们与铁电相互作用的竞争。同步加速器X射线和其他散射和成像技术将被用来探测阳离子耦合和电子跃迁，可能会引起反铁电性中观察到的异常特征。这项研究将进一步补充体和薄膜反铁电体的性能表征，以了解相变，界面运动，界面缺陷的相互作用，和反铁电/铁电竞争在最小的长度尺度的热力学和动力学。反铁电钙钛矿是迄今为止应用相对有限并且过去研究少得多的钙钛矿类型。 然而，理论上的考虑表明，这些材料可能具有独特的性质，因此对它们的基础研究将对用于重要技术和生物医学应用的铁电体产生根本性影响。该项目将培养博士。学生以及为本科生和高中教师提供培训。这项工作将纳入研究项目，以吸引传统和非传统的学生，并为他们提供实验室和研究的机会。