MRI: Acquisition of a Monochromated, Magnetic-Field-Free, Atomic-Resolution Scanning Transmission Electron Microscope Enabling Multidisciplinary Research and Education

MRI：获取单色、无磁场、原子分辨率扫描透射电子显微镜，实现多学科研究和教育

• 批准号: 2215976
• 负责人: Robert Klie
• 金额: $ 399万
• 依托单位: University of Illinois at Chicago
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2215976&HistoricalAwards=false
• 关键词: MRI; Acquisition; Monochromated; Magnetic; Field

Non-technical Description:Nanometer scale materials represent a class of substances with at least one dimension that approaches the size of individual atoms. These materials exhibit properties that are dramatically different from substances at larger length scales and are essential to advance a wide array of technologies, ranging from magnetic data-storage systems to superconducting quantum computers to biomaterials applications. To study and improve upon these materials, tools are required to examine them at the atomic level while minimizing any disturbance to their structure. Electron microscopy, which uses electrons to "see" atoms, is one of the fundamental means by which the structures of such nanoscale materials can be studied. Current designs of high-resolution transmission electron microscopes require a lens to focus the electron beam on the sample surface. A side effect of this design is that the sample material is inadvertently exposed to a high magnetic field. Yet, turning the lens off to eliminate the magnetic field when studying magnetic or superconducting materials makes atomic-resolution analysis impossible. The instrument acquired through this major research instrumentation grant has a new lens design, providing a magnetic-field-free sample region and, when combined with a nearly mono-energetic electron source, allows for atomic-resolution imaging as well as chemical analysis of these critical materials. In addition, atomic resolution, magnetic-field-free analysis can now also be achieved during heating or cooling experiments or when a controlled magnetic field is applied. To reach a broader user community and for communicating the capabilities of the instrument, the principal investigators hold annual workshops, organize sessions at national and international conferences, and engage with local microscopy societies. The instrument, moreover, provides the diverse undergraduate and graduate student body at University of Illinois - Chicago (UIC), a Research-1 Hispanic-serving institution with opportunities for hands-on research and learning experiences in cutting-edge quantum, superconducting or biomaterials science. New in-class course modules and online teaching resources are developed and freely distributed online using data from the field-free transmission electron microscope.Technical Description:While the development of aberration-correctors, monochromated electron sources, and advanced detectors has fueled the current revolution in resolution, nearly all high-resolution transmission electron microscopy (TEM) experiments are still performed with the sample being exposed to a high magnetic field, since the objective lens (OL) pole-pieces require a magnetic field of about 3 tesla. Such a magnetic field limits the samples that can be studied, preventing magnetic, magneto-optical, magneto-electric, superconductive or topological materials from being characterized under relevant conditions. Traditional magnetic imaging methods, where the OL is turned off, limit the spatial resolution to nanometer length-scales and do not allow for atomic-resolution chemical analysis. This instrument has a novel lens design that allows for better than 100 pm spatial resolution at 200 kV with a residual magnetic field of less than 0.3 mT and 40 meV energy resolution with a probe size of 110 nm. Atomic-resolution chemical analysis, as well as novel image modes, such as 4D-STEM and differential phase contrast imaging, can be combined with in-situ heating or cooling experiments to study magnetic, superconducting or other electronic phase transitions. Research projects at UIC enabled by the new instrument include the study of novel magnetic phases in Ni-based perovskite oxides, excitons in 2-dimensional materials, conventional and near-room temperature superconductors, nanoparticles/quantum dots as topological insulators, and anti-cavity biofilms and the mechanical manipulation of cells. External users, ranging from universities, national laboratories and companies across the United States to international partner institutions, can take advantage of the capabilities provided by the instrument to study novel quantum materials, new magnetic structures, photovoltaic materials, energy-storage devices, and biological systems under controlled magnetic-field conditions and with atomic resolution.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：纳米比例材料代表一类具有至少一个维度的物质，该物质接近单个原子的大小。这些材料表现出与较大长度尺度的物质截然不同的特性，对于推进广泛的技术至关重要，从磁性数据存储系统到超导量子计算机到生物材料应用。为了研究和改进这些材料，需要工具才能在原子水平上检查它们，同时最大程度地减少对其结构的干扰。电子显微镜使用电子来“看到”原子，是可以研究这种纳米级材料结构的基本手段之一。高分辨率透射电子显微镜的电流设计需要透镜将电子束聚焦在样品表面上。该设计的副作用是，样品材料无意间暴露于高磁场上。然而，在研究磁或超导材料时，关闭镜头以消除磁场，使原子分辨率分析不可能。通过此主要研究仪器获得的仪器具有新的透镜设计，提供了无磁场样品区域，并且与几乎单一的能电子源相结合时，可以进行原子分辨率成像以及对这些关键材料的化学分析。此外，在加热或冷却实验中或应用受控磁场时，也可以实现原子分辨率，现在也可以实现无磁场分析。为了达到更广泛的用户社区并传达工具的能力，首席调查人员举行年度研讨会，在国家和国际会议上组织会议，并与当地的显微镜社会互动。此外，该乐器为伊利诺伊大学 - 芝加哥大学（UIC）提供了多元化的本科生和研究生团体，这是一家研究-1西班牙裔服务机构，为尖端量子，超导或生物材料科学方面的动手研究和学习经验提供了机会。新的课堂课程模块和在线教学资源是使用来自无现场传输电子显微镜的数据开发和自由在线分发的。技术描述：虽然像纠正率，单色电子源的发展，并且高级探测器在分辨率上促进了当前的分辨率革命，但几乎所有的磁场都持续到了较高的磁场。 （OL）钢管需要大约3特斯拉的磁场。这样的磁场限制了可以研究的样品，以防止磁性，磁光，磁电磁性，超导或拓扑材料在相关条件下的表征。传统的磁成像方法，即关闭OL，将空间分辨率限制为纳米长度尺度，并且不允许原子分辨率化学分析。该仪器具有一种新颖的镜头设计，可在200 kV下的空间分辨率高于100 kV，残留磁场小于0.3吨和40 meV能量分辨率，探针大小为110 nm。原子分辨率化学分析以及新型图像模式（例如4D茎和差异相比成像）可以与原位加热或冷却实验结合使用，以研究磁性，超导或其他电子相变。新仪器启用UIC的研究项目包括研究基于Ni的钙钛矿氧化物中的新型磁相，二维材料中的激子，传统和近室温度超导体，纳米粒子/量子点作为拓扑绝缘子，以及抗钙腔生物膜以及细胞的机械操纵。外部用户，从美国的大学，国家实验室和公司到国际合作伙伴机构，都可以利用该工具提供的能力来研究新型量子材料，新的磁性结构，新磁性结构，光伏材料，能源存储措施，能量存储措施以及基于控制的磁场条件的生物学系统，并通过原子范围进行了基础。更广泛的影响审查标准。