Non-equilibrium Phase Discovery in Finite-sized Systems

非技术性总结具有改进性能的新材料的发现是技术进步的驱动力。具有这种改进的潜在丰富的领域是在正常条件下不能稳定形成的系统。 在这种情况下，“正常条件”和“稳定”意味着热力学平衡，这是一种科学的说法，因为它处于热，机械，化学和辐射平衡中，所以不会随着时间的推移而改变。通过避免平衡，可以获得材料的新构型，并且这些新构型可能具有新的和更好的性质。在这个项目中，平衡将通过创建非常小的材料系统来避免，它们以人眼看不到的尺寸存在。通过直接从气相中冷凝尺寸为几纳米（1 x 10^-9 m）的固体颗粒，并保持纳米颗粒之间的隔离，可以迫使通常不会在一起的元素混合，从而对这些材料系统的物理性质产生显着影响。通过这种方式，可以发现和开发新的磁性材料，对能量转换产生潜在的深远影响，以改善电机，发电机，数据存储甚至生物医学设备。此外，将导致对非常非常小的系统中的材料行为和结构形成的更好理解。该项目还侧重于培养下一代科学家。该项目将支持一名研究生，他将学习先进的材料制造，表征和建模技术，同时与国际合作伙伴合作。该项目还为本科社区学院学生转入四年制科学或工程（即，STEM）学位课程，目标是缓解向大学环境的过渡。最后，该项目将与现有的教师研究经验计划合作，为社区大学或高中科学教师及其学生提供纳米技术的教育机会。本项目将探索非平衡材料领域，通过创建孤立的，有限尺寸的系统来避免体积平衡。这将通过使用惰性气体冷凝来产生纳米量级的纳米颗粒来实现，这些纳米颗粒将彼此隔离。专注于通常不混溶的系统，新型固溶体合金和新的有序结构（即，金属间化合物）。此外，通过控制纳米颗粒的尺寸，可以探索尺寸依赖的相形成，在温度-组成相图中增加另一个轴。惰性气体冷凝是在大的组成空间上形成各种纳米材料的理想方法，并且可以很好地控制它们的尺寸。 特别地，在小的纳米颗粒尺寸下，发生完全或扩展的固溶体形成，对磁行为具有强烈的影响。 在这里，重点将是与4d和5d过渡金属如W和Mo合金化的Fe和Co，其中广泛的固溶体形成可以对磁行为产生深远的影响，以及Cu，Ag和Au，它们不混溶，但可能有形成非平衡金属间化合物的倾向。 这些调查将与意大利热那亚大学的研究人员进行的计算研究合作进行。 从该项目中获得的知识将扩大对纳米级合金和结构形成的理解，并开发用于能量转换系统，数据存储和生物医学应用的新材料。最终，这个项目提供了一条途径，探索隐藏在体积平衡中的未被发现的结构世界。 该项目还为一名研究生和一名本科社区学院学生转读四年制科学或工程（即，STEM）学位课程，目标是减轻向大学的过渡。最后，该项目将与现有的教师研究经验计划合作，为社区大学或高中科学教师及其学生提供纳米技术教育机会。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。

NON-TECHNICAL SUMMARYThe discovery of new materials with improved properties is a driver for technological advancement. An area potentially abundant with such improvements are systems that under normal conditions, cannot be formed stably. In this context, "normal conditions” and “stably” mean thermodynamic equilibrium, which is a scientific way of saying something will not change over time because it is in thermal, mechanical, chemical and radiative balance. By avoiding equilibrium, new configurations of materials can be accessed, and these new configurations may having new and better properties. In this project, equilibrium will be avoided by creating systems of material that are so small, they exist at a size invisible to the human eye. By condensing solid particles directly from a gas phase, with dimensions of a few nanometers, (1 x 10^-9 m) and maintaining isolation between the nanoparticles, elements which normally don’t go together, can be forced into mixing, thereby producing dramatic effects on the physical properties of these material systems. In this way, new magnetic materials can be discovered and developed, with potentially profound impacts on energy conversion to improve motors, generators, data storage, and even biomedical devices. Furthermore, a better understanding of materials behavior and structure formation in very, very small systems will result. This project is also focused on training the next generation of scientist. This project will support a graduate student who will learn advanced materials fabrication, characterization, and modeling techniques, while working with international partners. The project also provides support for an undergraduate community college student transferring to a four-year science or engineering (i.e., STEM) degree program, with the goal to ease the transition to the university environment. Finally, this project will partner with an existing Research Experience for Teachers Program, providing educational opportunities in nanotechnology for community college or high school science teachers as well as their students. TECHNICAL SUMMARYThis project will explore the field of non-equilibrium materials, by avoiding bulk equilibrium by creating isolated, finite-sized systems. This will be accomplished by using inert gas condensation to create nanoparticles on the order of nanometers, which will be isolated from one another. Focusing on normally immiscible systems, novel solid solution alloys and new ordered structures (i.e., intermetallic compounds) are expected to form. In addition, by controlling the size of the nanoparticles, the size-dependent phase formation can be explored, adding another axis to the temperature-composition phase diagram. Inert gas condensation is an ideal method of forming a wide variety of nanomaterials over large composition space, with excellent control over their size. In particular, at small nanoparticle sizes, complete or extended solid solution formation occurs, with strong effects on the magnetic behavior. Here, the focus will be on Fe and Co alloyed with 4d and 5d transition metals such as W and Mo, where extensive solid solution formation can have profound effects on the magnetic behavior, as well as Cu, Ag, and Au, with which they are immiscible but may have the propensity to form non-equilibrium intermetallic compounds. These investigations will be done in collaboration with computational studies by researchers at the University of Genoa, Italy. The knowledge gained from this project will expand the understanding of alloy and structure formation at the nanoscale, as well as develop new materials for energy conversion systems, data storage, and biomedical applications. Ultimately, this project provides a pathway to explore a world of undiscovered structures hidden by bulk equilibria. The project also provides support for a graduate student and an undergraduate community college student transferring to a four-year science or engineering (i.e., STEM) degree program, with the goal to ease the transition to the university. Finally, this project will partner with an existing Research Experience for Teacher program, providing nanotechnology educational opportunities for community college or high school science teachers and subsequently their students.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.