Magnetic Nanostructures with Perpendicular Anisotropy for Room Temperature Skyrmions

非技术摘要：磁天桥是遵循特定绕组配置的磁矩的一种特殊类型的排列。它们拥有一些令人着迷的特性。例如，它们不能连续变形到所有力矩指向同一方向的状态。Skyrmion磁性组态一旦形成就是稳定的，但一个关键的挑战是在环境条件下实现磁性Skyrmions。该项目的重点是建造人工天米子阵列，在高温下运行。利用一系列实验技术和模拟，研究了这些天子的物理性质。这些人造的天米子有望在室温和零磁场下保持稳定，因此是探索有趣的天米子物理的一个令人兴奋的新平台。它们还可能在高能效数据存储、磁存储器和逻辑设备中有潜在的应用。该项目提供了在大学以及国家实验室和用户设施中培训初级研究人员的机会。首席研究人员计划发起并积极参与各种努力，通过开设课程、实习、与伙伴大学交换访问以及其他特定计划，扩大代表不足群体的参与。技术摘要：基于垂直各向异性纳米结构的室温人造天米子晶格是在宏观区域实现的。采用多步纳米加工工艺实现了多种人工天米子，包括嵌入的天米子晶格、天米子“赛道”和弯曲衬底上的天米子晶格。遵循一组磁场序列来建立Skyrmion状态。通过微结构表征、磁测量、一阶反转曲线、磁成像、偏振中子反射仪和磁输运测量等手段，研究了天子群的空间分布、磁场分布、拓扑特征、稳定性、迁移率和对外界刺激的动态响应。模拟被用来为实验提供洞察和指导。这些研究不仅有助于促进对人工磁天子的基本认识，而且由于天子具有拓扑保护的量子态，因此在低耗散信息存储、磁存储和逻辑器件方面具有潜在的重要技术影响。它们还提供了在“超越摩尔定律”时代改变未来纳米电子能源格局的潜力，这与国家战略计算倡议和大数据倡议很好地结合在一起，以及未来纳米电子面临的重大挑战。首席调查员计划通过他对磁学界的广泛服务，发起并积极参与各种努力，以扩大国际社会、学生、女科学家和其他代表性不足群体的参与。参与该项目的学生可以很好地接触到大学、国家实验室和其他研究机构的研究经验。

Non-Technical Abstract:Magnetic skyrmions are a special type of arrangements of magnetic moments following a particular winding configuration. They possess some fascinating properties. For example, they cannot be continuously deformed to a state where all the moments point to the same direction. Skyrmion magnetic configurations are stable once they are formed, but a key challenge has been the realization of magnetic skyrmions at ambient conditions. This project focuses on construction of artificial skyrmion arrays, operational at elevated temperatures. The physical properties of these skyrmions are studied using a set of experimental techniques as well as simulations. These artificial skyrmions are expected to be stable even at room temperature and in zero magnetic field, thus are an exciting novel platform to explore the intriguing skyrmion physics. They also may have potential applications in highly energy-efficient data storage, magnetic memory and logic devices. This project provides opportunities to train junior researchers in university as well as national laboratory and user facilities. The principal investigator plans to initiate and actively participate in a variety of efforts to broaden participation from underrepresented groups through course offering, internships, exchange visits with partner universities, and other specific programs at the Magnetism Conference.Technical Abstract:Room temperature artificial skyrmion lattices based on nanostructures with perpendicular anisotropy are realized over macroscopic areas. A multi-step nanofabrication process is employed to achieve a variety of artificial magnetic skyrmions, including embedded skyrmion lattices, skyrmion "race-tracks", and skyrmion lattices on curved substrates. A set of magnetic field sequences is followed to establish the skyrmion states. Microstructural characterizations, magnetometry, first-order reversal curve, magnetic imaging, polarized neutron reflectometry, and magneto-transport measurements are carried out to probe the spatial and magnetic profile of skyrmions, their topological characteristics, stability, mobility, and dynamic responses to external stimuli. Simulations are employed to provide insight and guidance to the experiments. These studies not only help to advance fundamental understanding of artificial magnetic skyrmions, but also have potentially important technological impacts in low dissipation information storage, magnetic memory and logic devices, due to the topologically protected quantum states of the skyrmions. They also offer potentials to transform the energy landscape for future nanoelectronics in the "beyond Moore's law" era, which is well aligned with the National Strategic Computing Initiative and the Big Data Initiative, as well as grand challenges for future nanoelectronics. The principal investigator plans to initiate and actively participate in a wide variety of efforts to broaden participation from the international community, students, female scientists and other underrepresented groups, through his extensive service to the magnetism community. Students involved in the project receive excellent exposure to research experience in university, national laboratory and other research facilities.