Lattice dynamics and phase transitions in multifunctional oxide nanomaterials studied by ultraviolet Raman spectroscop

紫外拉曼光谱研究多功能氧化物纳米材料的晶格动力学和相变

• 批准号: 2104918
• 负责人: Dmitri Tenne
• 金额: $ 45万
• 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: 2021
• 资助国家: 美国
• 起止时间: 2021-07-01 至 2024-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2104918&HistoricalAwards=false
• 关键词: Lattice; dynamics; phase; transitions; multifunctional

Non-technical description:In recent years, science and technology of electronic materials have moved towards artificially engineered thin films and multilayer structures at nanometer scales (one billionth of a meter). Nanoscale materials exhibit physical behavior drastically different from that of macroscopic materials, thus opening new opportunities for novel device applications. This project studies nanoscale ferroelectrics and multiferroics, a class of materials both interesting for fundamental research and practically important due to high potential for applications in various devices, such as computer memories, microwave electronic devices or in next-generation transistors. The research is closely integrated into the educational program at Boise State University, involving undergraduate and graduate students in research and training, thus making them well prepared for careers in physical sciences and materials engineering. Such graduates are on demand by electronics and materials industries, such as Micron Technology, Hewlett Packard, and other high-tech companies in Boise metropolitan area. The project promotes an active use of the state-of-the-art instrumentation for educational purposes and supports the development of new graduate programs. It broadens the involvement of students from under-represented groups in the cutting-edge scientific research. The project enhances Boise State’s strength in condensed-matter physics and materials science. Technical description:Complex metal oxides are a vast class of materials that have a wide variety of functional properties attractive for novel device applications. Among these functionalities are ferroelectricity and ferromagnetism, properties of materials to possess spontaneous electric polarization or magnetization, which can be switched by applying electric or magnetic field, respectively. Ferroelectrics and multiferroics, materials that exhibit both magnetic and ferroelectric ordering, have been in the focus of intensive research activity in the last several years, driven by potential new functionalities for novel device applications arising from the coupling between the electrical and magnetic order parameters. Artificially engineered thin films and multilayer structures at nanometer scales are of particular interest, due to new physical phenomena and properties dramatically different from those of homogeneous bulk ferroelectrics. This project utilizes variable-temperature Raman spectroscopy with ultraviolet excitation to address several issues of major importance for understanding the behavior of nanoscale ferroelectrics and multiferroics, focusing on size effects in ferroelectric nanomaterials and temperature-strain phase diagrams in thin films and heterostructures of novel materials predicted to have ferroelectric and multiferroic properties in strained thin film form. These results are used to test the predictions of thermodynamic and first-principles theories and combined with thorough characterization of structural, electrical and magnetic properties, leading to a more comprehensive understanding of nanoscale ferroelectricity and magnetoelectric coupling. 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.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术描述：近年来，电子材料科学技术已向纳米尺度（十亿分之一米）人工工程薄膜和多层结构发展，纳米尺度材料表现出与宏观材料显着不同的物理行为。该项目研究纳米级铁电体和多铁性材料，这对于基础研究来说很有趣，而且由于在各种设备（例如计算机存储器、微波电子设备或其他设备）中的应用潜力很大，因此具有实际意义。该研究与博伊西州立大学的教育计划紧密结合，让本科生和研究生参与研究和培训，从而为他们在物理科学和材料工程领域的职业生涯做好准备。该项目促进了博伊西都会区的最先进仪器的积极使用，并支持新研究生项目的开发。 .它拓宽了该项目增强了博伊西州立大学在凝聚态物理和材料科学方面的实力。 技术描述：复杂金属氧化物是一类具有多种功能的材料。这些功能对新型器件应用具有吸引力，其中包括铁电性和铁磁性，即材料具有自发电极化或磁化的特性，可以分别通过施加电场或磁场来切换。多铁性材料，即表现出磁性和铁电有序性的材料，在过去几年中一直是深入研究活动的焦点，这是由电学和磁有序参数之间的耦合产生的新型器件应用的潜在新功能推动的。由于新的物理现象和特性与均质体铁电体显着不同，纳米尺度的薄膜和多层结构特别令人感兴趣。该项目利用了紫外拉曼光谱。激励解决对理解纳米级铁电体和多铁性行为至关重要的几个问题，重点关注铁电纳米材料的尺寸效应和薄膜中的温度应变相图以及预计在应变薄膜中具有铁电性和多铁性的新型材料的异质结构这些结果用于检验热力学和第一性原理理论的预测，并与结构、电学和磁学特性的全面表征相结合，从而使人们对结构、电学和磁学性质有更全面的了解。拟议的研究将紧密融入博伊西州立大学的教育计划，积极让本科生和研究生参与研究和培训，并促进最先进的光学仪器的持续有效使用。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。