Superconducting Pinning with Artificially Prepared Nanostructures

人工制备纳米结构的超导钉扎

• 批准号: 0800207
• 负责人: Ivan Schuller
• 金额: $ 50万
• 依托单位: University of California-San Diego
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-08-01 至 2012-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0800207&HistoricalAwards=false
• 关键词: Superconducting; Pinning; Artificially; Prepared; Nanostructures

Non Technical AbstractVortices are prevalent in nature all the way from the atmosphere, charge and uncharged plasmas, magnetic and superconducting materials. An important issue in this field is the way to anchor these vortices, the so called "pinning" because physical properties are modified in fundamental ways if vortices are pinned. A particularly interesting physical situations arises in superconductors where the magnetic field penetrates the material by the formation of arrays of superconducting vortices. These vortices can be pinned by artificially prepared pinning arrays which can be produced using novel lithographic techniques. This project is dedicated to the study of fundamental issue which arise when superconducting vortices interact with nanostructured arrays. Issues such as the effect of the array geometry, materials, shape of the pinning sites will be studied.In addition to its basic research interest, these studies may lead to schemes for reducing spontaneous noise and enhancing the superconducting properties of the material.Technical AbstractThe study of vortex pinning in superconductors is an interesting basic research area, with implications for the fabrication of high critical current tapes and low noise superconducting devices. The interaction between artificially prepared pinning arrays and the superconducting vortex lattice leads to quantum matching phenomena which manifest as enhanced critical currents and decreased resistance at particular fields. This research project, will be dedicated to (a) finding the type of pinning structure which individually provides strong pinning of vortices, and (b) introducing appropriate "defects" within the periodic array of pins, such as stripes and/or random fluctuations on the pinning site positions. (a) will increase the domain wall energy for the periodic point pins and increase the magnetic field width for the periodic stripe pins, thereby reducing thermal fluctuations, while (b) can change the universality class of the commensurate phase, thereby suppressing thermal fluctuations in fundamental ways. The issues concerning (a) are mostly material-specific, involving the microscopic mechanism of individual vortex-pin interaction. The issues concerning (b) are statistical in nature, having to do with the collective interaction of the vortex lattice with the array of pins. Both of these issues will be investigate systematically, and through extensive experimental collaborations and interactions with theoretical groups active in the field.

非技术摘要涡流在自然界中普遍存在，包括大气、带电和不带电等离子体、磁性和超导材料。该领域的一个重要问题是锚定这些涡流的方式，即所谓的“钉扎”，因为如果涡流被钉扎，物理特性会发生根本性的改变。超导体中出现了一种特别有趣的物理情况，其中磁场通过形成超导涡旋阵列而穿透材料。这些涡流可以通过人工制备的钉扎阵列来钉扎，该钉扎阵列可以使用新颖的光刻技术来产生。该项目致力于研究超导涡旋与纳米结构阵列相互作用时出现的基本问题。将研究诸如阵列几何形状、材料、钉扎位点形状的影响等问题。除了其基础研究兴趣外，这些研究可能会带来减少自发噪声和增强材料超导性能的方案。技术摘要超导体中涡旋钉扎的研究是一个有趣的基础研究领域，对高临界电流带和低噪声超导器件的制造具有影响。人工制备的钉扎阵列和超导涡旋晶格之间的相互作用导致量子匹配现象，表现为特定场下临界电流的增强和电阻的降低。 该研究项目将致力于（a）寻找能够单独提供强大涡流钉扎的钉扎结构类型，以及（b）在钉扎周期性阵列中引入适当的“缺陷”，例如钉扎位点位置上的条纹和/或随机波动。 (a)将增加周期点针脚的畴壁能量和增加周期性条带针脚的磁场宽度，从而减少热波动，而(b)可以改变相应相位的普适性等级，从而从根本上抑制热波动。有关（a）的问题主要是特定于材料的，涉及单个涡旋销相互作用的微观机制。有关 (b) 的问题本质上是统计问题，与涡流晶格与销钉阵列的集体相互作用有关。这两个问题都将通过广泛的实验合作以及与活跃在​​该领域的理论团体的互动进行系统地研究。