MRI: Acquisition of a Fast-Pulse-Laser for a Local Electrode Atom Probe

非技术：原子探针是一种显微镜，可以对材料中的单个原子进行三维渲染。通过能够想象原子如何聚集在一起，科学家们能够理解并因此设计出改善能量转换、导电或磁数据存储的材料。阿拉巴马大学（UA）在这些和其他需要这种原子水平成像的领域有重点研究项目。UA的研究人员正在研究一种涂层，这种涂层可以改善用于先进发电机和飞机发动机的涡轮叶片的生命周期。此外，学院研究人员还资助了燃料电池材料的开发工作。UA拥有一个政府和工业赞助的磁记录研究中心。该中心在开发高存储密度、高灵敏度传感器和更快的逻辑器件（如晶体管）的材料方面有积极的计划。这些新技术的大部分材料都是基于氧化物的材料，它们是不良的导电体。从历史上看，原子探针需要导电材料（金属）。激光脉冲技术的最新进展使原子探针能够成像不良的电导体，如半导体和绝缘体。要求的激光连接到UA的原子探针将随后扩大材料的范围，可以在这些战略计划中进行表征。激光附件提供了一种独特的能力，可以促进与几个地区机构的合作，包括历史上的黑人学院和大学。此外，它还招收亚利桑那大学材料科学学科的学生。技术：在三维微观结构中精确定位单个原子的能力已经成为材料表征的基本需求，将实验观察与原子尺度建模联系起来。原子探针仪器场从感兴趣的样品中蒸发原子，这些样品是在位置敏感的质谱探测器上收集的。通过重建每个离子的轨迹路径和撞击位置，以接近原子精度为每个原子生成材料的体积重建渲染。从历史上看，为了使高压脉冲传播到样品的顶点以蒸发表面原子，原子探针样品需要导电。现在，激光的商业化发展使得不良导体（陶瓷和半导体）在蒸发过程中得到热辅助。阿拉巴马大学（UA）有几个利用电介质材料的研究项目。原子探针显微镜表征这些材料的能力将大大推进这些计划。例如，UA在下一代栅极值的高k介电HfO2上的努力表明，氮掺杂可以显著减少HfO2和Si之间的混合；然而，由于无法描述界面上细微的组成变化，对其基本的理解受到了阻碍。UA在巨磁阻传感器和隧道磁阻器件的自旋电子研究方面一直处于领先地位。原子探针表征这些薄膜堆中埋藏的氧化物界面的能力将进一步促进我们在测量特性和建模之间的联系。激光也将使我们能够现场蒸发脆性金属间化合物，如FePt，这是超高磁存储介质的候选者。最后，UA有活跃的能源研究项目。附着在原子探针上的激光将使我们能够表征PtRu合金的催化支撑结构，如石墨和氧化铝。同样，激光将增加表征用于发电涡轮叶片的热防护涂层中氧化垢形成的能力。UA的支持基础设施和人员装备精良，可以开发原子探针样品，并将激光的使用范围扩大到各种材料。增强的能力将保持亚利桑那大学作为国家分析机构的地位，并继续促进我们与HBCU机构的现有外联研究活动。

Non-technical: The atom probe is a microscope that allows three dimensional rendering of individual atoms in a material. By being able to image how atoms cluster together, scientists are able to understand and thereby engineer materials for improved energy conversion, electrical conduction or magnetic data storage. The University of Alabama (UA) has key research programs in these and other areas that require this type of atomic level imaging. UA researchers are working on coatings that can improve the life cycle for turbine blades used in advanced power generators and aircraft engines. Additionally, faculty researchers have sponsored efforts in developing materials for fuel cells. UA houses a government and industrial sponsored magnetic recording research center. This center has active programs in developing materials for high storage densities, high sensitivity sensors and faster logic devices, such as transistors. Most of these materials for these new technologies use oxide-based materials, which are poor electrical conductors. Historically, atom probes required materials that were electrically conductive (metals). Recent advances in laser pulsing has allowed atom probes to image poor electrical conductors, such as semiconductors and insulators. The requested laser attachment to UA's atom probe will subsequently expand the range of materials that can be characterized in these strategic programs. The laser attachment provides a unique capability in fostering collaboration with several regional institutions, including historically black colleges and universities. Additionally, it serves in recruitment of students into the materials science discipline at UA. Technical: The ability to pin-point an individual atom in a three-dimensional microstructure has become an essential need in materials characterization to link experimental observations to atomic scale modeling. The atom probe instrument field evaporates atoms from a specimen of interest which are collected on a position-sensitive, mass-spectrum detector. By reconstructing the trajectory path and impact position of each ion, a volumetric reconstructed rendering of the material is generated with near atomic precision for each individual atom. Historically, atom probe specimens needed to be conductive in order for the high voltage pulse to propagate to the apex of the specimen to field evaporate the surface atoms. The commercial advent of the laser now allows poor conductors (ceramics and semiconductors) to be thermally assisted in the evaporation process. The University of Alabama (UA) has several research programs that utilize dielectric materials. The ability to characterize these materials by atom probe microscopy would significantly advance these programs. For example, UA's efforts on high-k dielectric HfO2 for next-generation gate-values has shown that nitrogen-doping can significantly reduce intermixing between HfO2 and Si; however, an underlying understanding has been hampered by the inability to characterize subtle composition changes at the interface. UA has a track-record of being leaders in spintronic research for giant magnetoresistance sensors and tunneling magnetoresistance devices. The atom probe's ability to characterize buried oxide interfaces within these thin film stacks would further facilitate our linkage between measured properties and modeling. The laser would also allow us to field evaporate brittle intermetallics, like FePt, that are candidates for ultrahigh magnetic storage media. Finally, UA has active energy-based research programs. The laser attachment to our atom probe would allow us to characterize PtRu alloys on their catalytic support structures, such as graphite and alumina. Similarly, the laser will increase the capability to characterize oxide scale formation in thermal protective coatings used for power generation turbine blades. UA's supporting infrastructure and personnel is exceptionally well equipped to develop atom probe specimens and advance the usage of the laser to a wide range of materials. The increased capability will maintain UA as a national analytical facility and continue to foster our existing outreach research activities with HBCU institutions.