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酸盐配位聚合物的电磁特性和结构特性之间的相互作用。 特别是，异质结构薄膜和颗粒的制造增加了界面与体积之比，从而使成分之间边界处的应力/应变效应主导了性能。 值得注意的是，光照射可以在液氮温度下对磁性进行持续的光控制，这项工作试图探索不同的途径将这种特性扩展到室温。 与此同时，量子自旋链也将被研究，重点放在S = 2材料上。 将探讨一维量子自旋和经典自旋之间的边界，并探讨局域磁环境各向异性的影响。 这两个研究重点都将采用压力作为外部参数，并且这些基于分子的磁体比传统的固态磁体更加柔韧。 物理和化学研究生直接参与研究项目的各个方面，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。 这些工具可在研究人员的当地实验室或国家设施中使用，例如国家高磁场实验室 (NHMFL)、橡树岭国家实验室 (ORNL) 的散裂中子源 (SNS) 和高通量同位素反应堆 (HFIR) .****非技术摘要****新现象的发现和新设备的开发现已达到成熟水平，需要越来越复杂的材料作为纳米尺寸薄膜和颗粒的成分。 沿着这个方向，基于分子的磁体是优异的材料，因为它们的特性可以通过合成方案进行调整，并通过外部刺激（例如温度、磁场、压力/应力/应变和光照射）进行控制。 在该研究项目中，对历史上作为油漆颜料产生的材料进行了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从外部控制。 敏感响应是由不同成分之间的界面处产生的应力和应变产生的，并且需要纳米长度尺度来减少块体材料贡献的静态背景。该研究旨在将这种控制扩展到更高的温度和新颖的形态，从而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。 最终的目标是增加对环境敏感材料中磁和电子相互作用之间相互作用的了解，这些材料的生产成本低廉。

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