Field- and Current-Driven Domain Wall Dynamics in Microstructures

技术摘要：在外加磁场和电流的作用下，可以在纳米级的空间尺度上高速操纵磁畴壁。现代纳米技术方法可以用来设计和制造纳米级的磁线。这些模型一维结构可以作为电流的管道和引导磁畴壁。该项目利用磁光技术来探索在制造的纳米级磁结构中对磁畴壁的高速操纵。这项工作的目标是描述和理解(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，以及：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高速操纵磁性：磁性元材料、记忆和逻辑结构以及成像、雷达和电信技术。这项研究涉及最先进的材料合成和纳米制造技术，并解决了由于纳米空间限制而出现的新现象。它为从事该项目的学生和博士后提供了极好的教育和培训机会。非技术摘要：在磁性材料(磁性纳米线)的一维纳米级结构中，电子自旋形成由磁区墙分隔的均匀磁化区域(磁区)，其中两个相反的自旋区之间的自旋取向相反。纳米结构中的自旋构型可以通过施加磁场或电流来操纵。在纳米尺度上高速操纵和探测电子自旋(局部磁性)的能力具有重要的技术意义：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以数字方式存储和处理信息的微电子设备。这个项目探索了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了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控制和限制局部磁性。该项目为培训下一代科学家、技术员和教师提供了一个很好的场所，因为它涉及新的现象，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.