RII Track 4: Metrology and spectroscopy of individual nanomagnets dynamics using quantum sensor-based (NV- center) nano-magnetometry

RII 轨道 4：使用基于量子传感器（NV 中心）纳米磁力测量的单个纳米磁体动力学的计量学和光谱学

• 批准号: 2033210
• 负责人: Kapildeb Ambal
• 金额: $ 20.93万
• 依托单位: Wichita State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-02-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2033210&HistoricalAwards=false
• 关键词: RII; Track; Metrology; spectroscopy; individual

Magnetic nanostructures, referred to as nanomagnets, are the foundation of emerging information storage technologies such as magnetic random access memory (MRAM) devices. Explosive growth in information science and technology sectors demands new storage technologies that are smaller recording bits, densely packed, fast, low-cost, and energy-efficient. Therefore, the magnetic nanostructures used to build magnetic memory need to be small, fast, and uniform across many devices. However, identically engineered nanomagnets' performances deviate from each other due to geometric imperfections, non-uniform material compositions, and manufacturing-related defects. A detailed diagnosis of individual nanomagnets is necessary to unravel the effects of shape, sizes, and manufacturing imperfections on nanomagnets' properties. However, the measurement of nanomagnets' properties is complicated because they are small and buried under many layers. The proposed project aims to measure the properties of individual nanomagnets. The proposed measurement would expose what causes the nanomagnets' performances to deviate from each other. The proposed research will be performed with a collaborator at the University of Nebraska – Lincoln (UNL). The state-of-the-art research tools at the Nebraska Nanoscale Facility will be used to design, fabricate, and measure nanomagnets' properties. The obtained new knowledge will be implemented into the education plans, which empower the future STEM workforce.The confined geometry of magnetic nanostructures causes spin dynamics to deviate from bulk thin films. In addition to shifting the resonance frequency, multiple spin-wave modes are present. The strong inhomogeneity in the internal magnetic field at the edge allows spin-wave to localize within a few nanometers from the edge. Damages induced during nanopatterning, such as impurities, edge, and interface roughness, can significantly modify spin dynamics. The edges and defects' roles become critical with decreasing size as the spin dynamics deviate among nanomagnets due to a slight deviation in edge roughness and defect densities. The measurement of spin dynamics is complicated because nanomagnets are often buried under nonmagnetic layers, and both conventional metrology tools and routine magnetic measurements are not adequately sensitive. Furthermore, it is difficult to retrieve an individual nanomagnet's covert spin dynamics from the average response of many similar nanomagnets. The proposed research investigates the spectroscopy of spin-wave excitation modes characteristics of individual magnetic nanostructures. The overall goals are to understand the fundamental device physics that controls the dynamic properties of magnetic nanostructures and to understand the source of defects, non-uniformity, and geometrical imperfection among devices and their roles in device performances. The proposed novel method is scanning Nitrogen-Vacancy (NV-) center-based magnetometry combined with real-time locking and tracking of NV- center's magnetic resonance peak. The proposed approach leverage the unique properties of NV- centers whose magnetic resonance frequency shifts due to change in the magnetic field in the vicinity.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.

磁性纳米结构，称为纳米磁铁，是诸如磁性随机存取存储器(MRAM)设备等新兴信息存储技术的基础。信息科学和技术领域的爆炸性增长要求新的存储技术，即更小的记录比特、密集打包、快速、低成本和高能效。因此，用于构建磁记忆的磁性纳米结构需要小、快，并且在许多设备上都是均匀的。然而，由于几何缺陷、材料组成不均匀以及与制造相关的缺陷，相同工程的纳米磁体的性能相互偏离。有必要对单个纳米磁体进行详细的诊断，以揭示形状、大小和制造缺陷对纳米磁体性能的影响。然而，纳米磁铁的性质测量很复杂，因为它们很小，埋在很多层下面。这项拟议的项目旨在测量单个纳米磁铁的性质。拟议的测量将揭示是什么导致纳米磁铁的性能相互偏离。这项拟议的研究将与内布拉斯加-林肯大学(UNL)的一名合作者一起进行。内布拉斯加州纳米尺度设施的最先进的研究工具将用于设计、制造和测量纳米磁铁的性能。所获得的新知识将被落实到教育计划中，从而为未来的STEM工作提供支持。磁性纳米结构的受限几何结构导致自旋动力学偏离块状薄膜。除了移动共振频率外，还存在多个自旋波模式。边缘内部磁场的强烈不均匀性允许自旋波在距离边缘几纳米的范围内局域化。在纳米粒子过程中产生的损伤，如杂质、边缘和界面粗糙度，可以显著地改变自旋动力学。随着尺寸的减小，边缘和缺陷的作用变得至关重要，因为由于边缘粗糙度和缺陷密度的轻微偏差，自旋动力学在纳米磁铁之间发生了偏差。自旋动力学的测量是复杂的，因为纳米磁铁通常被埋在非磁性的层下，而传统的计量工具和常规的磁性测量都不够灵敏。此外，很难从许多类似纳米磁体的平均响应中恢复单个纳米磁体的隐蔽自旋动力学。这项研究旨在研究单个磁性纳米结构的自旋波激发模式的光谱特性。总体目标是了解控制磁性纳米结构动态特性的基本器件物理，了解器件中缺陷、不均匀和几何缺陷的来源及其在器件性能中的作用。提出的新方法是基于扫描氮空位中心(NV-Center)的磁测量，结合对NV-中心磁共振峰的实时锁定和跟踪。建议的方法利用了NV中心的独特性质，其磁共振频率因附近磁场的变化而发生偏移。该奖项反映了NSF的法定使命，并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，被认为值得支持。

项目成果

An Efficient Method to Create High-Density Nitrogen-Vacancy Centers in Cvd Diamond for Sensing Applications

• DOI: 10.1016/j.diamond.2023.110472
• 发表时间: 2023-01
• 期刊: SSRN Electronic Journal
• 作者: Prem Bahadur Karki;Rupak Timalsina;M. Dowran;Ayodimeji E. Aregbesola;A. Laraoui;K. Ambal

Nitrogen-Vacancy Magnetic Relaxometry of Nanoclustered Cytochrome C Proteins

• DOI: 10.1021/acs.nanolett.3c03843
• 发表时间: 2024-01-11
• 期刊: NANO LETTERS
• 影响因子: 10.8
• 作者: Lamichhane，Suvechhya;Timalsina，Rupak;Laraoui，Abdelghani
• 通讯作者: Laraoui，Abdelghani