SGER: Sublithographic Patterning of Nanoscale Spintronic Devices

目的：本提案的主要技术和科学目标将是制造超密集的铁磁纳米线阵列，并分别对其磁性和电子特性进行表征。这项工作将提供对纳米尺度磁性机制的深入了解，并为未来的工作奠定基础，从制造超致密磁存储器（~ 0.5 TBit/in2）和微波振荡器相干阵列到开发和探索纳米模式磁性超材料。技术优点：近年来，在纳米尺度上控制物质的结构和组成已经成为科学界和工程界面临的一个重大挑战。然而，这一挑战的广度所固有的是一个难得的机会，可以从一个新的角度来处理以前棘手的问题。例子包括使用受生物启发的有机模板，用于低温、定向、金属和半导体纳米晶体的合成，以及在混合有机-无机纳米级器件和电路中使用分子材料作为活性层。本提案提出了另一种这样的融合，在利用新的亚光刻图图化技术和基于自旋传递扭矩机制的自旋电子器件和电路的发展之间的内在兼容性。这种相容性源于自旋转移转矩的振幅取决于自旋电流密度，因此自然适合于纳米级几何形状。与此同时，超晶格纳米线模式转移（SNAP）技术的发展，用于创建极其密集和索引良好的纳米线的大规模并行阵列（1000条线的间距低至20纳米），已经允许以接近晶体密度的方式创建多达16万个结的交叉棒电路。该提案的重点将是在Fe， Co和Ni合金中实施这种方法，允许以前所未有的密度制造磁性纳米线，并为尺寸小到超顺磁极限的磁性隧道结奠定基础。这些结构具有潜在的应用前景，包括超密磁随机存取存储器（MRAM）、电子和光学超材料以及相参微波阵列。更广泛的影响：纳米级系统固有的挑战的广度的第二个后果是，它需要相应的知识广度来开发给定问题的众多潜在解决方案。从另一个角度考虑这一挑战，纳米科学/纳米技术的研究也提供了一个令人兴奋的机会，为科学和工程职业培训的学生和广大公众提供了对许多传统上不同学科的见解。因此，该项目将纳入一个综合计划，既为学生的跨学科研究做好准备，又为未来在社区的推广工作奠定基础。该计划的核心将是纳米科学/纳米技术跨学科课程的发展，目标是高年级本科生和一年级研究生。本课程将分为三个模块，分别为物理、化学和生物，每个模块将介绍为什么纳米科学与相应的学科相关，以及纳米技术特定方面隐含的技术和应用。每个模块将由相关领域的专家讲师授课，课程将尽可能广泛地宣传，以鼓励来自不同背景的学生报名。显然，把每个学生都培养成这三个学科的专家是不现实的，本课程的目标将是为物理科学提供一种罗塞塔石碑。更具体地说，向学生介绍他们的同事认为重要的问题和解决方案，以便在他们未来的职业生涯中培养富有成效和成功的跨学科合作。这些活动将为未来高中水平的合作课程开发以及包括哥伦布科学博物馆在内的推广项目奠定基础。

SGER: Sublithographic Patterning of Nanoscale Spintronic Devices Objective: The primary technical and scientific objectives of this proposal will be the fabrication of ultra-dense arrays of ferromagnetic nanowires and their magnetic and electronic characterization, respectively. This work will provide insight into the mechanisms of nanoscale magnetism and lay the groundwork for future work ranging from the fabrication of ultra-dense magnetic memories (~ 0.5 TBit/in2) and coherent arrays of microwave oscillators to the development and exploration of nanopatterned magnetic meta-materials.Technical Merit: In recent years, control over the structure and composition of matter at nanoscopic length scales has emerged as a grand challenge facing the scientific and engineering communities. Inherent in the breadth of this challenge, however, is a remarkable opportunity to approach previously intractable problems from a new perspective. Examples include the use of biologically inspired organic templating for the low temperature, orientation specific, synthesis of both metallic and semiconducting nanocrystals and the use of molecular materials as active layers in hybrid organic-inorganic nanoscale devices and circuits. This proposal presents another such convergence, in exploiting an inherent compatibility between novel sublithographic patterning techniques and the development of spintronic devices and circuits based on the spin-transfer torque mechanism. This compatibility arises from the fact that the amplitude of the spin-transfer torque depends on spin current density, and therefore naturally lends itself to nanoscale geometries. In parallel, the development of the superlattice nanowire pattern transfer (SNAP) technique for creating massively parallel arrays of extremely dense and well indexed nanowires (1000's of wires at a pitch down to 20 nm) has allowed for the creation of crossbar circuits of up to 160,000 junctions at nearly crystallographic density. The focus of this proposal will be the implementation of this approach in Fe, Co, and Ni alloys, allowing the fabrication of magnetic nanowires at unprecedented density and laying the groundwork for magnetic tunnel junctions at sizes down to the superparamagnetic limit. These structures have potential applications including ultra-dense magnetic random access memories (MRAM), electronic and optical metamaterials, and phase coherent microwave arrays.Broader Impact: A second consequence of the breadth of the challenge inherent in nanoscale systems is that it requires a commensurate breadth of knowledge to exploit the multitude of potential solutions to a given problem. Considering this challenge from another perspective, the study of nanoscience/nanotechnology also provides an exciting opportunity to provide insight into a number of traditionally distinct disciplines, both for students training in careers in science and engineering and for the public at large. As a result, this program will incorporate an integrated plan to both prepare students for interdisciplinary research as well as lay the foundation for future outreach efforts in the community. The centerpiece of this program will be the development of an interdisciplinary course in nanoscience/nanotechnology aimed at upper level undergraduates and first year graduate students. The course will be broken into three modules, one each for physics, chemistry, and biology, and each module will provide an introduction into both why nanoscience is relevant for the appropriate discipline and the techniques and applications implicit in that particular aspect of nanotechnology. Each module will be taught by an instructor expert in the pertinent area, and the class will be advertised as broadly as possible to encourage students from diverse backgrounds to enroll. As it is clearly not practical to train each student to the level of expert in all three disciplines, the goal of this course will be rather to provide a sort of Rosetta stone for the physical sciences. More specifically, to provide students with an introduction to both the problems and solutions considered important by their colleagues so as to foster productive and successful interdisciplinary collaboration in their future careers. These activities will lay the foundation for future collaborative course development at the high school level, as well as outreach programs involving the Columbus science museum, COSI.