Magnetic order in disordered dipolar nanostructures

无序偶极纳米结构中的磁序

• 批准号: 2203933
• 负责人: Robert Streubel
• 金额: $ 51.71万
• 依托单位: University of Nebraska-Lincoln
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-06-01 至 2025-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2203933&HistoricalAwards=false
• 关键词: Magnetic; order; disordered; dipolar; nanostructures

This project is jointly funded by Condensed Matter Physics and the Established Program to Stimulate Competitive Research (EPSCoR).Non-technical abstractThis project aims to identify factors that affect magnetic properties of nanoparticle assemblies, including ferromagnetic liquid droplets and hydrogel sensors, so that they can be used for critical health and technology applications. Ferromagnetic liquid droplets are liquid bodies that can take and sustain virtually any shape while in liquid environment and can transition between a non-magnetic object and a permanent magnet. These unique properties could find application in drug delivery, microfluidic channels, and actuators. Smart hydrogel sensors are envisioned for continuous health monitoring due to their biocompatibility and sensitivity to, e.g., water acidity, that enlarges or shrinks the hydrogel. Embedded magnetic nanoparticles undergo a phase transition that can be detected without the need for electric wires into or out of the human body. This project provides mentored research training and career development to graduate and undergraduate students and leverages institutional services to recruit underrepresented students. The principal investigator engages the science-curious public and high school students in the proposed research via existing university services, social media, local conferences, and National Science Foundation-funded outreach programs and integrates his findings into undergraduate and graduate courses. Technical abstractMagnetic order by disorder is a complex non-trivial phenomenon that governs the transition between a vanishing (superparamagnetic) and a stable (ferromagnetic) magnetization with long-range, quasi-long-range, or short-range order. This complexity is even larger in liquid systems that undergo a reversible transformation between paramagnetic ferrofluid and ferromagnetic liquid by the assembly and jamming of superparamagnetic nanoparticles on curved liquid-liquid interfaces. The interfacial assembly is mediated by oppositely charged ligands that anchor the nanoparticles and reduce their electrostatic charge and spacing. The goal of this project is to determine design strategies for disordered ensembles of superparamagnetic nanostructures that combine reversible transformation between superparamagnetism and ferromagnetism with hard-magnetic properties. The principal investigator accomplishes this by studying the relationship between structural short-range order and magnetic properties in the dried state using nanoparticle assemblies and lithographically patterned nanostructures with different degrees of disorder, symmetry, layer thickness, and spacing and applying these findings to ferromagnetic liquid droplets. Through coordinated experimental and numerical studies using micromagnetic Monte Carlo simulations, magnetometry, ferromagnetic resonance spectroscopy, and advanced x-ray and electron microscopies, the principal investigator corroborates or refutes the following three hypotheses: (1) Materials with increasing disorder favor a transition from ferromagnetism to non-collinear magnetization to superparamagnetism that is delayed in anisotropic arrangements; (2) Structural short-range order governing magnetic order can be inferred from macroscopic properties; and (3) In-field assembly and jamming of nanoparticles at liquid-liquid interfaces enable nanopatterning of the surfactants with an enhanced remanent magnetization and coercive field.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.

该项目由凝聚态物理学和刺激竞争研究的既定计划共同资助。Non-technical Abstrack This This This Project旨在确定影响纳米颗粒组件的磁性特性的因素，包括铁磁性液滴和水凝胶传感器，以便将其用于关键的健康和技术应用。铁磁液滴是液体，在液体环境中几乎可以采用并维持任何形状，并且可以在非磁性物体和永久磁铁之间过渡。这些独特的特性可以在药物输送，微流体通道和执行器中找到应用。设想智能水凝胶传感器可以进行连续的健康监测，因为它们的生物相容性和对水酸度的敏感性，可以扩大或收缩水凝胶。嵌入的磁性纳米颗粒经历了可以检测到的相变，而无需电线进入或从人体中出来。该项目为研究生和本科生提供了指导的研究培训和职业发展，并利用机构服务来招募代表性不足的学生。首席研究人员通过现有的大学服务，社交媒体，地方会议以及国家科学基金会资助的外展计划与科学充满信心的公众和高中生参与了拟议的研究，并将其发现纳入本科和研究生课程。技术摘要磁性序列是一种复杂的非平凡现象，它控制着消失的（超paragnetic）和稳定（铁磁）磁化，并具有远距离，准距离或短距离顺序。在液体系统中，这种复杂性甚至更大，该液体系统通过组装和卡在弯曲的液态液体界面上的超顺磁性纳米颗粒的组装和堵塞。界面组件是由固定纳米颗粒并减少其静电电荷和间距的相对电荷配体介导的。该项目的目的是确定超级磁性纳米结构的无序集合的设计策略，这些纳米结构结合了超paragnetism和铁磁性与硬磁性的可逆转换。主要研究者通过研究干燥状态下结构短距离顺序与磁性特性之间的关系来实现这一目标，并使用纳米颗粒组件以及具有不同程度的疾病，对称性，层厚度和间距以及将这些发现并将这些发现施加到铁磁液滴的情况下，具有不同程度的纳米结构。 Through coordinated experimental and numerical studies using micromagnetic Monte Carlo simulations, magnetometry, ferromagnetic resonance spectroscopy, and advanced x-ray and electron microscopies, the principal investigator corroborates or refutes the following three hypotheses: (1) Materials with increasing disorder favor a transition from ferromagnetism to non-collinear magnetization to superparamagnetism that is delayed in各向异性安排； （2）可以从宏观特性中推断出磁性顺序的结构短距离顺序； （3）在液体液体接口处的纳米颗粒的现场组装和纳米粒子可以通过增强的磁性磁化和强制性领域的纳米图案来实现纳米图案。该奖项反映了NSF的法定任务，并通过基金会的知识优点和广泛的影响来评估NSF的法定任务。

项目成果

Ballistic Ejection of Microdroplets from Overpacked Interfacial Assemblies

• DOI: 10.1002/adfm.202213844
• 发表时间: 2022-07
• 期刊: Advanced Functional Materials
• 影响因子: 19
• 作者: Xuefei Wu;Gautam Bordia;R. Streubel;J. Hasnain;C. Pedroso;B. Cohen;B. Rad;P. Ashby;A. Omar;P. Geissler;Dong Wang;Han Xue;Jianjun Wang;Thomas P. Russell

Angular dependence of the magnetization relaxation in Co/Pt multilayers

Co/Pt 多层膜中磁化弛豫的角度依赖性

• DOI: 10.1088/1361-648x/acfc8f
• 发表时间: 2023
• 期刊: Journal of Physics: Condensed Matter
• 作者: Adhikari, Anil;Herrington, Bryce;Nguyen, Nhat;Zielinski, Ruthi Linnea;Mahmood, Ather;Adenwalla, Shireen;Streubel, Robert
• 通讯作者: Streubel, Robert

Phase contrast imaging of non-collinear spin textures with Lorentz microscopy

• DOI: 10.1557/s43578-023-01216-1
• 发表时间: 2023-11
• 期刊: Journal of Materials Research
• 影响因子: 2.7
• 作者: R. Streubel

Self‐Propulsion by Directed Explosive Emulsification

定向爆炸乳化自推进

• DOI: 10.1002/adma.202310435
• 发表时间: 2024
• 期刊: Advanced Materials
• 影响因子: 29.4
• 作者: Wu, Xuefei;Xue, Han;Bordia, Gautam;Fink, Zachary;Kim, Paul Y.;Streubel, Robert;Han, Jiale;Helms, Brett A.;Ashby, Paul D.;Omar, Ahmad K.
• 通讯作者: Omar, Ahmad K.

Ferromagnetic resonators synthesized by metal-organic decomposition epitaxy

金属有机分解外延合成的铁磁谐振器

• DOI: 10.1088/1361-648x/acf35b
• 发表时间: 2023
• 期刊: Journal of Physics: Condensed Matter
• 作者: Nguyen, Nhat;Herrington, Bryce;Chorazewicz, Kayetan;Paul) Wang, Szu-Fan;Zielinski, Ruthi;Turner, John;Ashby, Paul D.;Kilic, Ufuk;Schubert, Eva;Schubert, Mathias
• 通讯作者: Schubert, Mathias