Raman Spectroscopy of Nanoscale Ferroelectric and Multiferroic Thin Films and Superlattices

纳米级铁电和多铁薄膜和超晶格的拉曼光谱

• 批准号: 1006136
• 负责人: Dmitri Tenne
• 金额: $ 28.5万
• 依托单位: Boise State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1006136&HistoricalAwards=false
• 关键词: Raman; Spectroscopy; Nanoscale; Ferroelectric; Multiferroic

****NON-TECHNICAL ABSTRACT****Modern science and technology of electronic materials increasingly focuses on the development of novel, artificially engineered structures on the nanometer (one billionth of a meter) scale. The physical behavior of materials at the nanoscale is principally different from that of macroscopic materials in many aspects, opening new opportunities for the design of materials with superior properties for device applications. This project will experimentally investigate the fundamental physical properties of nanoscale ferroelectrics and multiferroics, an interesting and practically important class of electronic materials with high potential for applications in various devices, such as computer memories or microwave electronic devices. The project will utilize optical spectroscopic techniques to probe fundamental properties related to the atomic vibrations and structural transformations under a variety of conditions. The experimental results of the project will test the validity of current theories of ferroelectrics and multiferroics, thereby contributing to a comprehensive understanding of their properties. The proposed research will be closely integrated into the educational program at Boise State University, involving undergraduate and graduate students in research and training, promoting an active use of the state-of-the-art optical instrumentation for educational purposes, and supporting the development of new graduate programs. ****TECHNICAL ABSTRACT****Ferroelectrics are materials possessing a spontaneous electric polarization, which can be switched by the application of an electric field. Ferroelectrics and multiferroics, materials that exhibit both magnetic and ferroelectric ordering, are the focus of much active research with an abundance of basic science to be studied and novel applications to be explored. In recent years, science and technology of ferroelectrics and multiferroics have moved towards artificially engineered thin films and multilayer structures at nanometer scales. The dynamics of lattice vibrations is a fundamental property of ferroelectrics, related to many of their important physical properties, and Raman spectroscopy is one of the most powerful analytical techniques for studying the lattice vibrations. This project will utilize ultraviolet Raman spectroscopy to address several issues of major importance for understanding the behavior of nanoscale ferroelectrics and multiferroics, such as temperature-strain phase diagrams of thin films and heterostructures, the effect of an electric field on lattice dynamics and phase transitions, effects of off-stoichiometry on the properties of homo- and heteroepitaxial ferroelectric films, and ferroelectric and structural transformations in strained films of novel materials. The proposed research will be closely integrated into the educational program at Boise State University, actively involving undergraduate and graduate students in research and training and promoting the continued effective use of the state-of-the-art optical instrumentation for educational purposes.

****非技术摘要****电子材料的现代科学技术越来越关注于纳米（十亿分之一米）尺度上的新型人工工程结构的发展。材料在纳米尺度上的物理行为在许多方面与宏观材料有很大的不同，这为设计具有优异性能的材料用于器件应用开辟了新的机会。该项目将通过实验研究纳米铁电体和多铁电体的基本物理性质，这是一类有趣且在实践中很重要的电子材料，在各种设备中具有很高的应用潜力，如计算机存储器或微波电子设备。该项目将利用光谱学技术来探测与各种条件下原子振动和结构转变有关的基本特性。该项目的实验结果将测试当前铁电体和多铁体理论的有效性，从而有助于全面了解它们的性质。拟议的研究将与博伊西州立大学的教育计划紧密结合，包括本科生和研究生的研究和培训，促进最先进的光学仪器的积极使用，用于教育目的，并支持新的研究生计划的发展。****技术摘要****铁电体是一种具有自发电极化的材料，可以通过施加电场来切换。铁电体和多铁材料，既具有磁性又具有铁电有序，是许多活跃研究的焦点，有大量的基础科学有待研究，新的应用有待探索。近年来，铁电体和多铁材料的科学技术向纳米尺度的人工工程薄膜和多层结构发展。晶格振动动力学是铁电体的基本性质，与铁电体的许多重要物理性质有关，而拉曼光谱是研究铁电体晶格振动的最有力的分析技术之一。该项目将利用紫外拉曼光谱来解决几个对理解纳米级铁电体和多铁电体的行为具有重要意义的问题，如薄膜和异质结构的温度-应变相图，电场对晶格动力学和相变的影响，非化学配比对同质和异质外延铁电膜性能的影响，新材料应变薄膜中的铁电和结构转变。拟议的研究将与博伊西州立大学的教育计划紧密结合，积极参与本科生和研究生的研究和培训，并促进教育目的中最先进光学仪器的持续有效使用。