Materials World Network: Ultrafast All-Optical Switching in Ferri-/Ferromagnetic Nanomagnets

技术摘要：在国家科学基金会材料研究部(DMR)和德国科学基金会的资助下，Holger Schmidt(加州大学圣克鲁斯分校)的应用光学小组和Manfred Albrecht(德国开姆尼茨理工大学)的磁性纳米结构小组将合作研究全光磁化开关在铁磁和亚铁磁性纳米磁体中的技术、材料和应用。具体的项目目标包括：(I)展示使用亚铁磁性材料的单域纳米磁体中的全光磁化开关；(Ii)利用磁各向异性、居里温度和结晶学可调的磁性材料制造交换耦合异质结构；(Iii)展示单个纳米磁体在铁磁和铁磁材料的各种组合中的超快开关；以及(Iv)研究作为三维纳米磁体和密集阵列中的磁环境的函数的全光开关过程。这项研究是通过结合Albrecht集团的材料专业知识和施密特集团开发的单个纳米磁体检测能力来实现的。非技术摘要：纳米磁体被考虑用于下一代数据存储介质和其他自旋电子学应用已经有一段时间了。最近，亚铁磁性材料中磁取向的超快全光开关的发现引起了人们的极大兴趣，因为它有可能创造出具有前所未有的响应时间的数据存储介质。这种光开关层与交换耦合的铁磁存储层的潜在组合非常耐人寻味，并提出了许多令人兴奋的材料问题。该项目将在纳米存储介质的背景下系统地探索这种材料的新组合。此外，该项目将通过创造独特和有益的教育体验，为不同水平的学生提供比单一国家环境下可能的更广泛和更完整的教育。参与小组之间在相当长的时间内(每年2-4周)相互访问，将允许对其合作者所使用的技术进行有意义的培训，以扩大学生的知识、沟通技能和职业竞争力。除了一名研究生和一名博士后，来自代表性不足群体的本科生将通过UC Leads或UC Camp计划招募，并将有机会与国外研究人员合作完成他们的高级论文。

TECHNICAL SUMMARY: With financial support provided by the Division of Materials Research (DMR) at the National Science Foundation and the Deutsche Forschungsgemeinschaft, this collaborative effort between the Applied Optics group of Holger Schmidt (UC Santa Cruz, USA) and the Magnetic Nanostructures group of Manfred Albrecht (Chemnitz University of Technology, Germany) will investigate techniques, materials, and applications of all-optical magnetization switching in ferro- and and ferrimagnetic nanomagnets. Specific project goals include (i) demonstration of all-optical magnetization switching in single-domain nanomagnets using ferrimagnetic materials; (ii) fabrication of exchange-coupled heterostructures using magnetic materials with adjustable magnetic anisotropy, Curie temperature, and crystallography; (iii) demonstration of ultrafast switching of single nanomagnets in various combinations of ferro- and ferromagnetic materials; and (iv) investigation of the all-optical switching process as a function of the three-dimensional nanomagnet, and the magnetic environment in a dense array. This research is enabled through the combination of the materials expertise of the Albrecht group and the single nanomagnet detection capabilities developed in the Schmidt group.NON-TECHNICAL SUMMARY: Nanomagnets have been under consideration for next generation data storage media and other spintronics applications for some time. Recently, the discovery of ultrafast all-optical switching of magnetic orientation in ferrimagnetic materials has received a lot of interest due to the potential to create data storage media with unprecedented response times. The potential combination of such an optical switching layer with an exchange-coupled ferromagnetic storage layer is highly intriguing and raises a number of exciting material questions. This project will systematically explore novel combinations of such materials in the context of nanoscale storage media. In addition, the project will provide students at different levels with a broader and more complete education than what would be possible in a uni-national setting by creating a unique and rewarding educational experience. Mutual visits between the participating groups for a substantial amount of time (2-4 weeks per year) will allow for meaningful training in the technique used by their collaborators to broaden student knowledge, communication skills, and professional competitiveness. Aside from one graduate student and one postdoc, undergraduate students from underrepresented groups will be recruited through the UC LEADS or UC CAMP program, and will be given the opportunity to complete their senior theses in collaboration with researchers from abroad.