Spectroscopy of molecule-based materials in high magnetic fields

高磁场中分子材料的光谱学

• 批准号: 1063880
• 负责人: Janice Musfeldt
• 金额: $ 41.7万
• 依托单位: University of Tennessee Knoxville
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-08-01 至 2015-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1063880&HistoricalAwards=false
• 关键词: Spectroscopy; molecule; based; materials; magnetic

TECHNICAL SUMMARY:The research outlined in this proposal, supported by the Solid State and Materials Chemistry Program, focuses on the optical and magneto-optical properties of molecule-based materials with the overarching goal of understanding the consequences of physical and chemical tuning on functionality. Building on key advances in the previous award period, this program concentrates on (i) magnetoelastic coupling in chemically simple molecular magnets, (ii) photophysical properties of quantum spin ladders and organic biradicals, and (iii) the interplay between charge, structure, and magnetism in these systems. Within these broad scientific areas, several model compounds that may show large or widely applicable magneto-optical effects have been identified. Examples include a series of chemically-related transition metal and mixed-metal cyanide systems like Mn(dca)2 and Cr(Ru2)3 with magnetic ordering and quantum critical transitions through which local lattice distortions can be analyzed. Also included are spin ladders like Cu(qnx)Cl2 and organic biradicals such as 1,4-diphenylenenitrene, where the color properties can be tuned with magnetic field. These materials offer additional complexity in their behavior compared to the S = 1/2 copper halide coordination polymers where novel high field effects were originally discovered yet they are well-controlled enough to act as model systems to meaningfully explore the phenomenology of quantum magnetism. What brings these efforts together is a common focus on coupling and functionality deriving from the interplay between charge, structure, and magnetism and the high field spectroscopic techniques that we use to investigate these phenomena. Findings from this comprehensive experimental program will further complementary research on magnetic oxides as well as theoretical development and device applications.NON-TECHNICAL SUMMARY:The overall goal of this program is to investigate the behavior of materials under extreme conditions, specifically those of very high magnetic fields. Two criteria are required to meet this objective. First, the target materials must have low energy scales, commensurate with experimentally realizable magnetic fields. Second, they must be soft enough to respond to an applied field. Molecular materials meet these benchmarks. While dynamical measurements reveal the interplay between charge, structure, and magnetism and provide broad insight into functionalities that depend upon such coupling, they also impart understanding of similar processes in higher energy scale materials like oxides where experimentally available magnetic fields are often insufficient to drive the most interesting transitions, some of which may be useful for magneto-optical devices. This program leverages the Joint Institute of Advanced Materials at the University of Tennessee and Oak Ridge National Laboratory, the facilities at the National High Magnetic Field Laboratory in Tallahassee and Los Alamos, and numerous connections with researchers at other academic institutions and national laboratories. At the same time, it supports the interdisciplinary education and training of a diverse group of young people for future employment in academics, government laboratories, and industry in the area of advanced materials. A broad range of educational, outreach, and service activities will also take place under the auspices of this National Science Foundation funded program, especially in the area of conference and workshop organization.

该提案中概述的研究由固态和材料化学计划支持，重点关注分子基材料的光学和磁光特性，其总体目标是了解物理和化学调谐对功能的影响。在上一个奖项期间的关键进展的基础上，该计划集中在（i）化学简单分子磁体中的磁弹性耦合，（ii）量子自旋梯和有机双自由基的物理性质，以及（iii）这些系统中电荷，结构和磁性之间的相互作用。在这些广泛的科学领域内，已经确定了几种可能显示出大的或广泛适用的磁光效应的模型化合物。例子包括一系列化学相关的过渡金属和混合金属氰化物系统，如Mn（dca）2和Cr（Ru 2）3，具有磁有序和量子临界跃迁，通过这些系统可以分析局部晶格畸变。还包括像Cu（qnx）Cl 2这样的自旋梯和像1，4-diphenylenenitrene这样的有机双自由基，其中颜色特性可以用磁场来调节。与S = 1/2卤化铜配位聚合物相比，这些材料在其行为中提供了额外的复杂性，其中最初发现了新颖的高场效应，但它们被良好地控制，足以作为模型系统来有意义地探索量子磁性的现象学。是什么把这些努力结合在一起是一个共同的重点耦合和功能来自电荷，结构和磁性之间的相互作用和高场光谱技术，我们用来调查这些现象。从这个综合性的实验计划的结果将进一步补充磁性氧化物的研究以及理论发展和设备的应用。非技术摘要：该计划的总体目标是调查材料在极端条件下的行为，特别是那些非常高的磁场。实现这一目标需要两个标准。首先，靶材料必须具有低能量尺度，与实验上可实现的磁场相称。第二，它们必须足够柔软，以响应应用领域。分子材料满足这些基准。虽然动态测量揭示了电荷，结构和磁性之间的相互作用，并提供了对依赖于这种耦合的功能的广泛了解，但它们也赋予了对更高能量尺度材料（如氧化物）中类似过程的理解，其中实验可用的磁场通常不足以驱动最有趣的转变，其中一些可能对磁光器件有用。该计划利用了田纳西大学和橡树岭国家实验室的先进材料联合研究所，塔拉哈西和洛斯阿拉莫斯国家高磁场实验室的设施，以及与其他学术机构和国家实验室研究人员的众多联系。与此同时，它支持跨学科的教育和培训的年轻人为未来的就业在学术界，政府实验室和先进材料领域的行业。一个广泛的教育，推广和服务活动也将在这个国家科学基金会资助的计划，特别是在会议和研讨会组织领域的主持下进行。