Dynamic Transitions in Magnetic Vortex Lattices

磁涡晶格中的动态转变

• 批准号: 0102692
• 负责人: Eva Andrei
• 金额: $ 34.5万
• 依托单位: Rutgers University New Brunswick
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-05-01 至 2005-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0102692&HistoricalAwards=false
• 关键词: Dynamic; Transitions; Magnetic; Vortex; Lattices

This individual investigator award will fund a project that will employ a new pinning-force microscope in conjunction with fast transport measurements, to address key questions on vortex dynamics. These include: a) the mechanism of current driven metastable to stable transitions; b) the nature of moving vortex phases and the transitions between them; c) effects of boundaries on dynamics and phase segregation in the peak effect region; d) the mechanism of frequency memory in vortex states. The planned pinning force microscope will image not the vortices themselves but the contrast between regions with different pinning forces. It will be capable of distinguishing between a strongly pinned disordered vortex state and a weakly pinned ordered one with spatial resolution of about 1micro-m, and its operation will not be limited to low fields. By taking advantage of the fact that the vortex motion can be frozen in place and that the imaging is non-invasive, the microscope will be capable of resolving vortex motion with excellent temporal resolution (about 1ms). This method will allow access to regimes of vortex dynamics not possible by existing vortex imaging techniques. The students and young researchers involved in this work will gain skill in applying newly developed new techniques to questions of interest. The knowledge and skills that they will learn will be of use to them in future research and development careers.%%%A limiting factor to the use of Type-II superconductors in technology is that at a particular magnetic field strength, magnetic vortices form. These vortices can become "de-pinned" which then cause the superconductor to loose its zero resistance state. Because most properties of Type-II superconductors are governed by the physics of vortices, it is of fundamental and technological interest to study the physics of the motion these vortices. Several newly discovered phenomena have made it clear that our present understanding of vortex dynamics (or motion) is flawed. It appears that, due to the presence of a random pinning force, the phase transitions and the onset of vortex motion are very interesting and more complex than originally thought. This individual investigator award will fund a program to address these issues by imaging the pinning force distribution in the vortex phases with a novel high resolution microscope that we propose to build in our laboratory. A strong educational component will be an integral part of the project. Students at both graduate and undergraduate levels as well as a post doctoral fellow will actively participate in all research and development aspects of the program. The knowledge and skills that they will learn will be of use to them in future research and development careers.***

该个人调查员奖将资助一个项目，该项目将与快速运输测量结果一起采用新的固定力显微镜，以解决有关涡流动力学的关键问题。 其中包括：a）当前驱动的稳定过渡的机理； b）移动涡流阶段的性质及其之间的过渡； c）边界对峰值效应区域动力学和相位分离的影响； d）涡旋状态中频率内存的机理。 计划的固定力显微镜将不是图像涡流本身，而是具有不同固定力的区域之间的对比。 它将能够区分强烈的无序涡流状态和一个弱固定有序的空间分辨率约为1micro-m，并且其运行不限于低场。 通过利用涡流运动可以冷冻到位并且成像是非侵入性的事实，显微镜将能够以极佳的时间分辨率（约1ms）解决涡流运动。 此方法将允许通过现有的涡流成像技术无法访问涡旋动力学的态度。 参与这项工作的学生和年轻研究人员将获得将新技术应用于感兴趣的问题的技巧。 他们将要学到的知识和技能将在未来的研发职业中对他们有用。%% %%在技术中使用II型超导体的限制因素是，在特定的磁场强度，磁性涡流形式下。 这些涡旋可能会变成“脱丁”，从而导致超导体松散其零电阻态。 由于II型超导体的大多数特性受涡流物理学的控制，因此研究这些涡旋的运动物理学具有基本和技术兴趣。 几种新发现的现象已经清楚地表明，我们目前对涡流动力学（或运动）的理解是有缺陷的。 看来，由于存在随机固定力，相变和涡流运动的发作非常有趣，而且比最初想象的更为复杂。 该个人调查员奖将资助一项计划，以通过将涡旋阶段的固定力分布成像，我们建议我们在实验室中建造涡旋阶段的固定力分布。 强大的教育组成部分将是该项目不可或缺的一部分。 研究生和本科生以及博士后研究员的学生都将积极参与该计划的所有研发方面。 他们将学习的知识和技能将在未来的研发职业中对他们有用。***