CAREER: Atomic-Scale Optical Microscopy of Ferroelectric, Quantum Paraelectric and Ferromagnetic Films

职业：铁电、量子顺电和铁磁薄膜的原子尺度光学显微镜

• 批准号: 9701725
• 负责人: Jeremy Levy
• 金额: $ 30万
• 依托单位: University of Pittsburgh
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-06-01 至 2002-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9701725&HistoricalAwards=false
• 关键词: CAREER; Atomic; Scale; Optical; Microscopy

9701725 Levy This CAREER project aims to develop high resolution spatially and temporally resolved near-field optical techniques to investigate nanometer-scale phenomena in two materials systems: (1) ferroelectrics, quantum paraelectrics, and (2) ultrathin magnetic films. The broad aim of this research is to probe dynamical processes at the short length and time scales, and to relate these observations to macroscopic properties. For ferroelectric thin films, domain reversal and domain wall dynamics will be imaged stroboscopically at MHz-THz frequencies, with the goal of understanding fundamental mechanisms for microwave dissipation and dielectric dispersion. Nonlinear interactions between impulsively generated coherent phonons, domain walls, charged impurities and grain boundaries will be studied with anticipated near-atomic spatial resolution, and time resolution below the phonon period. Time-resolved techniques will be used to probe order parameter fluctuations in order-disorder ferroelectrics, and to search for signatures of a macroscopically coherent ground state in quantum paraelectrics at low temperatures. For magnetic films, a newly proposed Kerr-effect near-field microscopy will be developed for the purpose of studying magnetization dynamics on fundamental length scales and time scales. The nature of biquadratic exchange in coupled ferromagnetic layers, and the role of dynamic versus thermodynamic fluctuations at the reorientation phase transition of ultrathin magnetic epilayers will also be addressed. %%% The project addresses forefront research issues in materials science. The research will contribute basic materials science knowledge at a fundamental atomic level to important aspects of ferroelectric and magnetic materials, in general. An important feature of the program is a special emphasis on education, and on the integration of research and education through the training of students in a fundamentally and technologically significant research area. ***

9701725该职业项目旨在在两种材料系统中研究纳米尺度现象，在空间和时间上解决高分辨率的高分辨率：（1）铁电器，量子paraelectrics和（2）超级磁性膜。这项研究的广泛目的是在短长和时间尺度上探测动态过程，并将这些观察结果与宏观特性联系起来。对于铁电薄膜，将在MHz-Thz频率下以频镜进行域逆转和域壁动力学，其目的是了解微波炉耗散和介电分散体的基本机制。将通过预期的接近原子空间分辨率以及低于声子周期的时间分辨率来研究冲动产生的相干声子，域壁，带电杂质和晶界之间的非线性相互作用。时间分辨技术将用于探测订单级铁电气中的订单参数波动，并在低温下搜索量子paraelectrics中宏观相干基态的签名。对于磁性膜，将开发新提出的KERR效应近场显微镜，目的是研究基本长度尺度和时间尺度上的磁化动力学。耦合的铁磁层中生物二级交换的性质以及动态与热力学波动在重新定向相变的作用也将得到解决。 %%％该项目解决了材料科学领域的最前沿研究问题。 总体而言，这项研究将在基本原子水平上为基本原子水平提供基本材料知识，从而为铁电和磁性材料的重要方面提供贡献。 该计划的一个重要特征是特别强调教育，以及通过在根本和技术意义上的研究领域中培训学生通过培训学生的研究和教育。 ***