Field- and Current-Driven Domain Wall Dynamics in Microstructures

技术摘要：磁畴壁可以通过外加磁场和电流在纳米空间尺度上进行高速操纵。现代纳米技术方法可用于设计和制造纳米级磁性线。这些模型一维结构可以作为电流的导管和磁畴壁的导向。本项目利用磁光技术来探测纳米级磁性结构中磁畴壁的高速操纵。这项工作的目标是表征和理解（自旋扭矩）机制：1)允许通过电流在纳米空间尺度上高速操纵磁化；2)控制能量损失和阻尼。这项工作与现有的和新兴的技术直接相关，这些技术依赖于在小空间尺度上对磁性的高速操纵：磁性元材料，存储器和逻辑结构，以及成像，雷达和电信技术。该研究涉及最先进的材料合成和纳米制造技术，并解决由于纳米空间限制而出现的新现象。它为参与项目的学生和博士后提供了良好的教育和培训机会。摘要：在磁性材料（磁性纳米线）的一维纳米尺度结构中，电子自旋形成均匀磁化的区域（畴），由畴壁隔开，其中自旋方向在两个相反的自旋畴之间反转。纳米结构中的自旋构型可以通过施加磁场或电流来控制。在纳米尺度上高速操纵和探测电子自旋（局部磁性）的能力在技术上是重要的：它为磁性细胞逻辑和相关的新设备技术提供了基础，这些技术可以扩展和改进现有的用于数字存储和处理信息的微电子设备。这个项目探索磁性纳米结构中电子自旋的高速操纵。这项工作的目标是确定和理解允许电流操纵自旋的机制，并发现材料成分和几何约束如何在纳米尺度上支配和限制局部磁性的控制。该项目为培养下一代科学家、技术人员和教师提供了一个很好的场所，因为它涉及到新的现象，并且需要应用当前最先进的研究仪器和材料科学/纳米科学技术。

Technical Abstract:Magnetic domain walls can be manipulated at high-speeds and on nanometer spatial scales by applied magnetic fields and electric currents. Modern nanotechnology methods can be used to engineer and fabricate nanometer-scale magnetic wires. These model one-dimensional structures can serve as conduits for electric current and for guiding magnetic domain walls. This project utilizes magneto-optic techniques to probe the high-speed manipulation of magnetic domain walls in fabricated nanometer-scale magnetic structures. The goal of the work is to characterize and understand the (spin-torque) mechanisms that: 1) allow high-speed manipulation of magnetization on nanometer spatial scales by electric currents, and that: 2) govern energy loss and damping. The work is directly related to existing and emerging technology that relies on high-speed manipulation of magnetism on small spatial scales: magnetic meta materials, memory and logic structures, and imaging, radar and telecommunication technology. The research involves state-of-the-art materials synthesis and nanofabrication techniques, and addresses new phenomena that occur as a result of nanometer spatial constraints. It provides excellent education and training opportunities for the students and postdoctoral associates who work on the projects.Non-Technical Abstract:Electron spins in one-dimensional nanometer-scale structures of magnetic material (magnetic nanowires) form regions of uniform magnetization (domains) separated by a domain wall in which spin orientation reverses between the two opposing spin domains. The spin configuration in the nanostructure can be manipulated by the application of a magnetic field or an electric current. The ability to manipulate and probe electron spins (local magnetism) on nanometer scales at high speeds is technologically important: it provides the basis for magnetic cellular logic and related new device technology that could extend and improve existing microelectronic devices that digitally store and process information. This project explores high-speed manipulation of electron spins in magnetic nanostructures. The objective of the work is to determine and understand the mechanisms that allow electric current manipulation of spins and discover how material composition and geometrical constraints govern and limit the control of local magnetism on nanometer scales. The project provides a good venue for training the next generation of scientists, technologists, and teachers because it involves new phenomena and requires application of current state-of the-art research instruments and materials science/nanoscience technology.