Quantum and Thermal Creep of Skyrmions and Superconducting Vortices

斯格明子和超导涡旋的量子和热蠕变

• 批准号: 1905909
• 负责人: Serena Eley
• 金额: $ 44万
• 依托单位: Colorado School of Mines
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-07-15 至 2023-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1905909&HistoricalAwards=false
• 关键词: Quantum; Thermal; Creep; Skyrmions; Superconducting

Non-technical Abstract: Vortices are topological excitations that appear in many different systems. In superconductors, vortices consist of supercurrents circulating around a non-superconducting core and are typically unwanted because their motion induces dissipation that often limits the performance of superconducting wires and devices in power, magnet, sensing, and computing applications. On the contrary, in certain magnetic materials, vortex-like excitations called skyrmions (winding configurations of magnetic moments) form which are predicted to be beneficial for use as information carriers in next-generation low-energy spintronic devices. Mitigating the deleterious effects of superconducting vortices and exploiting skyrmions in spintronic devices for magnetic memory and logic require a microscopic understanding of the complex interplay between vortices, material disorder, and thermal energy. In this work, the research team is investigating this interplay by comparing the rates of vortex and skyrmion motion in materials containing varying amounts of disorder. This research provides training for graduate and undergraduate students in low temperature measurement techniques, materials growth and microanalysis, and quantum materials physics, necessary skillsets in multiple industries including power, sensing, and computing. Additionally, the principal investigator is reaching out to the local community by organizing an annual Open House Community Day for which families in central Colorado will be invited to the Colorado School of Mines for lab tours, science demonstrations, and hands-on activities.Technical Abstract: The interaction of vortices with material disorder is a primary determinant of the electronic and magnetic properties of many systems. In type-II superconductors, vortices are magnetic flux lines that penetrate into the material upon exposure to magnetic fields. In chiral magnets and magnetic multilayers, vortex-like excitations called skyrmions (winding configurations of magnetic moments) can form due to antisymmetric, anisotropic exchange coupling between magnetic moments on lattice bonds. Though the origins of vortices in superconductors and skyrmions in magnetic systems are fundamentally different, striking similarities exist between their dynamics. For example, both can be modeled as particle-like excitations interacting with quench disorder, undergo disorder mediated collective interactions and exhibit glassines. Material disorder immobilizes vortices and skyrmions, whose motion can be induced by sufficiently high currents or thermal energy (thermal creep), or occur via quantum tunneling through disorder-defined energy barriers (quantum creep). Despite considerable previous research on superconductor vortex dynamics, serious gaps still exist in vortex physics. Creep rates are not predictable and no analytic expression exists that broadly captures the temperature and field dependence of creep. The objective of this work is to understand quantum creep of superconducting vortices and both quantum and thermal creep of skyrmions. To this end, the research team captures creep rates in many superconducting and magnetic materials in a range of temperatures and magnetic fields using magnetization and transport measurements. Subsequent comparisons of creep rates in disparate materials with varied disorder landscapes enables them to draw universal correlations between creep and fundamental material parameters. This research could fill a major gap in the understanding of how vortices overcome different energy barriers and enable efficacious design of defect landscapes in superconductors for many applications and magnetic devices for skyrmion-based spintronics.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术摘要：涡旋是出现在许多不同系统中的拓扑激发。在超导体中，涡流由围绕非超导核心循环的超电流组成，通常是不需要的，因为它们的运动会引起耗散，这通常会限制超导线材和设备在电力、磁体、传感和计算应用中的性能。 相反，在某些磁性材料中，形成称为斯格明子（磁矩的缠绕配置）的类涡旋激发，预计这将有利于在下一代低能自旋电子器件中用作信息载体。减轻超导涡旋的有害影响并利用自旋电子器件中的斯格明子进行磁记忆和逻辑需要对涡旋、材料无序和热能之间复杂的相互作用有微观的了解。在这项工作中，研究小组通过比较含有不同数量无序的材料中的涡旋和斯格明子运动速率来研究这种相互作用。 该研究为研究生和本科生提供低温测量技术、材料生长和微分析、量子材料物理、电力、传感和计算等多个行业的必要技能的培训。此外，首席研究员还通过组织一年一度的开放日社区日来接触当地社区，科罗拉多州中部的家庭将被邀请到科罗拉多矿业学院进行实验室参观、科学演示和实践活动。 技术摘要：涡流与材料无序的相互作用是许多系统的电子和磁性特性的主要决定因素。在 II 型超导体中，涡流是暴露在磁场中时穿透材料的磁通线。在手性磁体和磁性多层中，由于晶格键上磁矩之间的反对称、各向异性交换耦合，可以形成称为斯格明子（磁矩的缠绕配置）的涡旋状激发。尽管超导体中的涡旋和磁系统中的斯格明子的起源根本不同，但它们的动力学之间存在惊人的相似之处。例如，两者都可以被建模为与猝灭无序相互作用的类粒子激发，经历无序介导的集体相互作用并表现出玻璃光泽。材料无序固定涡流和斯格明子，其运动可以由足够高的电流或热能引起（热蠕变），或者通过量子隧道穿过无序定义的能量势垒（量子蠕变）而发生。 尽管先前对超导涡旋动力学进行了大量研究，但涡旋物理学仍然存在严重差距。蠕变速率是不可预测的，并且不存在广泛捕获蠕变的温度和场依赖性的分析表达式。这项工作的目的是了解超导涡旋的量子蠕变以及斯格明子的量子蠕变和热蠕变。为此，研究团队利用磁化和输运测量来捕获许多超导和磁性材料在一定温度和磁场范围内的蠕变速率。随后对具有不同无序景观的不同材料的蠕变速率进行比较，使他们能够得出蠕变和基本材料参数之间的普遍相关性。这项研究可以填补理解涡流如何克服不同能量势垒的重大空白，并能够有效设计用于许多应用的超导体中的缺陷景观以及用于基于斯格明子的自旋电子学的磁性器件。该奖项反映了 NSF 的法定使命，并被认为是值得的通过使用基金会的智力优势和更广泛的影响审查标准进行评估来提供支持。

项目成果

Observation of anti-damping spin–orbit torques generated by in-plane and out-of-plane spin polarizations in MnPd3

MnPd3 中面内和面外自旋极化产生的反阻尼自旋轨道扭矩的观察

• DOI: 10.1038/s41563-023-01522-3
• 发表时间: 2023-05
• 期刊: Nature Materials
• 影响因子: 41.2
• 作者: DC, Mahendra;Shao, Ding;Hou, Vincent D.;Vailionis, Arturas;Quarterman, P.;Habiboglu, Ali;Venuti, M. B.;Xue, Fen;Huang, Yen;Lee, Chien;et al
• 通讯作者: et al

Vortex phases and glassy dynamics in the highly anisotropic superconductor HgBa2CuO4+δ

高各向异性超导体 HgBa2CuO4 δ 中的涡旋相和玻璃态动力学

• DOI: 10.1038/s41598-020-65224-5
• 发表时间: 2019-09-04
• 期刊: Scientific Reports
• 影响因子: 4.6
• 作者: S. Eley;R. Willa;M. Chan;E. Bauer;L. Civale
• 通讯作者: L. Civale

Plastic vortex creep and dimensional crossovers in the highly anisotropic superconductor HgBa2CuO4+x

高各向异性超导体 HgBa2CuO4 x 中的塑性涡旋蠕变和维度交叉

• DOI: 10.1103/physrevb.107.104509
• 发表时间: 2023-03
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Cole, Haley M.;Venuti, Michael B.;Gorman, Brian;Bauer, Eric D.;Chan, Mun K.;Eley, Serena
• 通讯作者: Eley, Serena

Designing high-performance superconductors with nanoparticle inclusions: Comparisons to strong pinning theory

设计具有纳米粒子夹杂物的高性能超导体：与强钉扎理论的比较

• DOI: 10.1063/5.0057479
• 发表时间: 2021-05-21
• 期刊: APL Materials
• 影响因子: 6.1
• 作者: Sarah C. Jones;M. Miura;Ryuji Yoshida;T. Kato;L. Civale;R. Willa;S. Eley
• 通讯作者: S. Eley

Challenges and transformative opportunities in superconductor vortex physics

超导涡旋物理的挑战和变革机遇

• DOI: 10.1063/5.0055611
• 发表时间: 2021-04-30
• 期刊: Journal of Applied Physics
• 影响因子: 3.2
• 作者: S. Eley;A. Glatz;R. Willa
• 通讯作者: R. Willa