Magnetic Correlations and Control in Nanoscaled Molecule-based Magnets

纳米级分子磁体中的磁相关性和控制

• 批准号: 1202033
• 负责人: Mark Meisel
• 金额: $ 34.5万
• 依托单位: University of Florida
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-06-01 至 2016-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1202033&HistoricalAwards=false
• 关键词: Magnetic; Correlations; Control; Nanoscaled; Molecule

****Technical Abstract****This research explores the interplay between the electromagnetic and structural properties of cyanometallate coordination polymers. Specially, the fabrication of heterostructured films and particles increases the interface to bulk ratio, thereby allowing the stress/strain effects at the boundaries between the constituents to dominate the properties. Notably, irradiation with light allows persistent photocontrol of the magnetism up to liquid nitrogen temperatures, and this work seeks to explore different paths to extend this property to room temperature. In parallel, quantum spin chains will also be studied, and the emphasis is placed on S = 2 materials. The boundary between quantum and classical spins in one-dimension will be probed, and the influence of the anisotropy of the local magnetic environment will be explored. Both research thrusts will employ pressure as an external parameter, and these molecule-based magnets are significantly more pliable than their traditional solid-state counterparts. Physics and chemistry graduate students participate directly in every aspect of the research program and receive unique training in a variety of techniques, including magnetometry, X-ray and neutron scattering, and high-field, high-frequency magnetic resonance techniques. The tools are available in the local laboratories of the investigators or at national facilities like the National High Magnetic Field Laboratory (NHMFL), and the Spallation Neutron Source (SNS) and High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL).****Non-Technical Abstract****The discovery of novel phenomena and the development of new devices have now reached levels of maturity where increasingly complex materials are required as constituents of nanometer sized films and particles. Along this direction, molecule-based magnets are excellent materials because their properties can be tuned by synthesis protocols and controlled by external stimuli such as temperature, magnetic field, pressure/stress/strain, and irradiation by light. In this research program, materials historically generated as paint pigments are modified and employed in nanoscaled films and particles whose novel magnetic and optical properties can be externally controlled. The sensitive response results from stress and strain developed at the interface between the different constituents, and the nanometer length scales are required to diminish the static background that the bulk material contributes. The research seeks to extend this control to higher temperatures and in novel morphologies that can provide new magneto-optical switches and light harvesting devices. A variety of interdisciplinary tools, including magnetometry, electron microscopy, X-ray scattering, and magnetic resonance, are used to characterize the samples. Physics and chemistry graduate students are trained using state-of-the-art instrumentation and data analysis techniques, and undergraduate students are integrated into various aspects of the work. Ultimately, the goal is to increase the knowledge of the interplay between magnetic and electronic interactions in environmentally sensitive materials that are inexpensive to generate.

* 技术摘要 * 本研究探讨了氰基金属配位聚合物的电磁和结构特性之间的相互作用。 特别地，异质结构膜和颗粒的制造增加了界面与体积比，从而允许组分之间的边界处的应力/应变效应主导性质。 值得注意的是，用光照射可以在液氮温度下对磁性进行持久的光控，这项工作旨在探索不同的途径将这种特性扩展到室温。 同时，量子自旋链也将被研究，重点放在S = 2材料上。 在一维量子和经典自旋之间的边界将被探测，并探讨局部磁环境的各向异性的影响。 这两项研究都将采用压力作为外部参数，这些基于分子的磁体比传统的固态磁体要柔韧得多。 物理和化学研究生直接参与研究计划的各个方面，并接受各种技术的独特培训，包括磁力测量，X射线和中子散射，以及高场，高频磁共振技术。 这些工具可在调查人员的当地实验室或国家设施中获得，如国家高磁场实验室（NHMFL）和橡树岭国家实验室（ORNL）的Spanitus中子源（SNS）和高通量同位素反应堆（HFIR）。非技术摘要 * 新现象的发现和新器件的开发现已达到成熟水平，其中需要越来越复杂的材料作为纳米尺寸的膜和颗粒的成分。 沿着这个方向，分子基磁体是优异的材料，因为它们的性质可以通过合成方案来调节，并通过外部刺激（例如温度、磁场、压力/应力/应变和光照射）来控制。 在这项研究计划中，历史上作为油漆颜料产生的材料被改性并用于纳米级薄膜和颗粒，其新颖的磁性和光学特性可以外部控制。 敏感的响应结果从应力和应变之间的不同成分的界面处开发，和纳米的长度尺度是必要的，以减少静态的背景下，散装材料的贡献。该研究旨在将这种控制扩展到更高的温度和新的形态，可以提供新的磁光开关和光捕获设备。 各种跨学科工具，包括磁力测量、电子显微镜、X射线散射和磁共振，用于表征样品。物理和化学研究生使用最先进的仪器和数据分析技术进行培训，本科生则融入工作的各个方面。 最终，目标是增加对环境敏感材料中磁性和电子相互作用之间相互作用的了解，这些材料的产生成本低廉。

项目成果

Light-induced magnetization changes in aggregated and isolated cobalt ferrite nanoparticles

聚集和分离的钴铁氧体纳米颗粒的光诱导磁化强度变化

• DOI: 10.1063/1.5040327
• 发表时间: 2018
• 期刊: Journal of Applied Physics
• 影响因子: 3.2
• 作者: Brinzari, Tatiana V.;Rajan, Divya;Ferreira, Cauê F.;Stoian, Sebastian A.;Quintero, Pedro A.;Meisel, Mark W.;Talham, Daniel R.
• 通讯作者: Talham, Daniel R.

Unusual Magnetic Response of an S = 1 Antiferromagetic Linear-Chain Material

• DOI: 10.1088/1742-6596/969/1/012121
• 发表时间: 2014-09
• 期刊: Journal of Physics: Conference Series
• 作者: J. Xia;A. Ożarowski;P. Spurgeon;Adora G. Graham;J. Manson;M. Meisel